Compared to Without Video Assistant Referee: Does Video Assistant Referee Monitoring Have an Impact on the Chinese Super League?

Compared to Without Video Assistant Referee: Does Video Assistant Referee Monitoring Have an Impact on the Chinese Super League? | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Compared to Without Video Assistant Referee: Does Video Assistant Referee Monitoring Have an Impact on the Chinese Super League? Bo Zhang, Mingyuan Lin, Delihai Qi, Liqing Zhang, Pei Deng This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5663513/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 May, 2025 Read the published version in BMC Sports Science, Medicine and Rehabilitation → Version 1 posted 6 You are reading this latest preprint version Abstract Background Even though the Chinese Super League (CSL) introduced Video Assistant Referees (VARs) in the 2018 season, it did not intervene in every game. The Hawthorne effect highlights how human behavior can change when individuals are aware they are being observed. VARs monitoring means VAR just introduces but does not intervene in the games. Thus, this research compared the performance in the games where VARs did not intervene and without VARs, to investigate whether VARs monitoring influences match performance, similar to the Hawthorne effect. Methods The sample includes matches in which VARs were not applied in the 2014–2017 season (n = 1920) and in which VARs were not intervened in the 2018–2021 season (n = 528). The Generalized Linear Mixed Model was used to examine the different variables in different groups. Results The study found that after the implementation of VARs in the game, the percentage of non-intervention was 32 percent. Even though VARs was not applied, it had a significant impact on goals ( p < 0.01, Cohen’s d = 0.04), penalties ( p < 0.001, Cohen’s d = 0.07), free kicks ( p < 0.001, Cohen’s d = 0.18), tackles ( p < 0.001, Cohen’s d = 0.13), fouls ( p < 0.01, Cohen’s d = 0.11), and red cards ( p 0.05). Conclusions In the CSL, VARs intervenes frequently in matches. VARs monitoring also had a certain degree of impact on sports performance, especially defensive performance. In addition, VARs monitoring follows the idea of FIFA to encourage attacking, and it also benefits limited fouls. Video assistant referee Hawthorne effect Chinese Super League Figures Figure 1 1. Introduction Since the laws of the football game have been applied , referees have used power to guide football games smoothly. However, the limitations of the subject [ 1 – 3 ] and object factors [ 4 , 5 ] are all detrimental to the fairness and spectacle of football matches. With the development of competitive sports, the demand for fairness in sports has intensified. Football matches have added a series of intelligent devices [ 6 ] , such as NFC smart chips, "earphones", and goal-line technology, to compensate for the referee's deficiency. For instance, goal-line technology uses sensors and chips to provide precise data, allowing referees to make accurate decisions. The implementation of the Video Assistant Referee system (VARs) by the Fédération Internationale de Football Association (FIFA) represents another technological advancement aimed at reducing the impact of human error. In matches, at least one video assistant referee (VAR), an assisting VAR (AVAR), and a replay operator (RO) are present in the Video operation room (VOR) to help the referee in the field to decision-making by viewing video [ 7 ] . Since its formal introduction at the 2018 FIFA World Cup [ 8 ] , VARs has been introduced in numerous national leagues, including in Spain, France, and China [ 9 ] . Numerous studies have highlighted many situational variables, such as game location [ 10 ] , quality of opposition [ 11 ] , and match time [ 12 ] , influencing players’ performance. With the application of VARs, many scholars have researched the impacts of VARs on different aspects of the game. Regarding football match time, the study [ 13 ] has shown that the time in the matches before and after the implementation of VARs has been increased. This result was also shown in the Women's World Cup [ 14 ] . For the Chinese Super League (CSL), the introduction of VARs led to an average increase of 2.39 minutes in effective playing time per game [ 15 ] . About the referee, VARs has improved decision accuracy, as evidenced by a rise in the referee accuracy rate from 92.1–98.3% in 13 national leagues [ 16 ] , and the World Cup in Russia data also shows increased accuracy [ 17 ] . Research on fans [ 18 – 20 ] , some studies found that fans viewed VARs as enhancing competitiveness and reducing pressure on referees [ 18 ] . In contrast, another research [ 19 ] observed that loyal fans are more positive about VARs introduction and are especially happy when a judgment is changed in favor of an opposing player. However, fans’ sentiments towards VARs are more skewed towards the negative by analyzing data from Twitter [ 20 ] . Concerning athletes, studies have shown that the intervention of VARs can impact athletes' performance, including high-speed running distance [ 21 ] , goals [ 22 ] , offside [ 23 ] , fouls [ 13 ] , and distance of low-speed running [ 21 ] . Moreover, much research [ 24 , 25 ] analyzed the effect of different numbers of interventions in a football match. While much research has focused on comparing matches with and without VARs interventions, no study has yet analyzed whether the mere presence of VARs monitoring affects player performance. This gap in the literature forms the basis of the study. Based on numerous studies, the introduction of VARs influence extends beyond the referees, potentially affecting match performance. The Hawthorne effect highlights how human behavior can change when individuals are aware they are being observed [ 26 ] . The discovery of the Hawthorne effect originated from the Hawthorne Factory Experiment, which challenged traditional studies and introduced new perspectives from psychology and sociology. In football games, although VARs doesn't intervene, players remain aware of the camera surveillance on the field. Whether the VARs has the same effect as the Hawthorne effect? Thus, building on the question and previous studies, the study compares the data from matches where VARs did not intervene (2018–2021 season) with those from the 2014–2017 seasons (without VARs). This study aims to explore whether the mere presence of VARs monitoring (without actual intervention) has an impact on match performance. Analyzing these performance changes offers valuable insights for football coaches, players, and other management, helping them understand how VARs influences the development of the game. 2. Methods 2.1Match Sample In the research, VARs non-intervention was defined as the use of VARs not resulting in a significant stoppage of games in the 2018–2021 season. The CSL in the 2014–2021 seasons (2014–2019 season, n = 240; 2020 season, n = 180; 2021 season, n = 176) has 1,796 matches. VARs intervened in a total of 552 matches in the 2018–2021 season, and VARs did not intervene in 264 matches. A lot of research shows that some contextual information, including game outcome [ 27 ] , game location [ 28 , 29 ] , and quality of opposition [ 30 ] influence the performance. Thus, situational variables of seasons, game location, quality of opposition and team was taken into account.1224 matches were divided into two groups: VAR-pre (without VARs, n = 1920), and VAR-post (VARs did not intervene in a match, n = 528). Referring to previous studies, the variables of match performance analyzed for each match included goals, penalties, shots, passes, free kicks, corners, tackles, fouls, yellow cards, and red cards. Based on other research [ 28 , 31 , 32 ] , the variables were divided into scoring (goal, shot, penalties), attacking (pass, free kick, corner), and defensive variables (tackles, fouls, yellow cards, and red cards). 2.2 Procedures All 816 matches in the 2018–2021 seasons were recorded by downloading video footage from Chinese match broadcasting platforms. The data of VARs intervention was collected by two observers, 20 matches were randomly selected for the study and the two observers made a duplicate collection and the data was tested for reliability. The calculation results showed that the Kappa value of reliability was 0.97. Then, the data of the matches without VARs intervention recording was collected by a single observer. The performance data analyzed in this study were primarily sourced from Creative Ice DATA ( http://data.champdas.com ), where the reliability of the data has been verified by previous scholarly research [ 33 ] . 2.3Analysis Descriptive statistics, including the mean and standard deviation, were calculated for the variables used in this study. The 95% confidence intervals of effects were calculated in Microsoft Excel 2007. In addition, the Generalized Linear Mixed Model was employed, with a significance threshold set at p < 0.05. Separate Poisson and Negative Binomial were run in the model. A fixed effect for VARs was used, the random effects estimated the effect of the game location, as well as the effect of season, team and opposition strength. The game location was with two levels (home, and away). The season was with eight levels. The effect of team and opponent strength was estimated by the end-of-season points. The thresholds of Cohen’s d for small, moderate, large, very large, and extremely large were 0.2, 0.6,1.2, 2.0, and 4.0 [ 34 ] , and GraphPad was employed for creating the graphical representations in the paper. 3. Results The research aimed to investigate the impact of VARs and analyzed the matches in which VARs did not intervene in the 2018–2021 season through the video observation method. The study found that VARs intervened in 552 matches, with just 264 matches in which the system did not intervene. The percentage of non-intervention was 32 percent. Table 1 The results of the Generalized Linear Mixed Model (N = 2448) Variables VAR-pre VAR-post F Cohen's d p value M ± SD M ± SD Goals 1.41 ± 6.51 1.19 ± 3.41 6.68 0.04 <0.01** Penalties 0.16 ± 1.24 0.08 ± 0.65 45.16 0.07 <0.001*** Shots 12.36 ± 37.18 11.54 ± 19.66 2.602 0.02 0.107 Passes 386.84 ± 547.48 403.29 ± 287.43 1.72 -0.03 0.19 Free Kicks 17.97 ± 13.94 15.63 ± 7.8 15.422 0.18 <0.001*** Corners 4.71 ± 15.28 4.79 ± 8.94 0.164 -0.01 0.686 Tackles 17.01 ± 13.01 15.41 ± 7.31 8.87 0.13 0.003** Fouls 15.62 ± 13.01 14.31 ± 7.31 7.48 0.11 0.006** Yellow Cards 1.91 ± 5.89 1.84 ± 32.01 0.57 0.00 0.449 Red Cards 0.08 ± 0.93 0.05 ± 0.49 10.81 0.04 <0.001*** Note. Significant level: ** P < 0.01, *** P < 0.0001 As can be seen in Table 1 and Fig. 1 , a significant difference ( p < 0.05) was found in the scoring variables of goals, and penalties. There was a significant decrease in goals [ ( p VAR-post, Cohen’s d = 0.04], penalty kicks [ p VAR-post, Cohen’s d = 0.07], However, there was no significant difference in the number of shots ( p > 0.05). The attacking variable of free kicks was obviously different ( p < 0.001). A significant decrease was shown in free kicks [( p VAR-post, Cohen’s d = 0.18]. However, there was no significant difference in the number of passes and corners ( p > 0.05). And the defense-related variables of fouls, tackles and red cards have significant differences ( p < 0.05), tackles [( p VAR-post, Cohen’s d = 0.13], fouls [ p VAR-post, Cohen’s d = 0.11] and red cards [ p VAR-post, Cohen’s d = 0.04] showed a significant decreased. While there was no significant difference in the number of yellow cards between the two groups ( p > 0.05). From Table 1 , the effect size of all significant variables shows a small effect. 4. Discussion This study investigates whether the mere presence of VARs monitoring, even without intervention, influences match performance. The research uncovered that VARs intervened more times in the CSL, only 32% of the matches in which VARs did not cause a significant pause in the game. In addition, the results indicate that performance indicators, including goals, penalties, fouls, free kicks, and red cards exhibited significant differences. It suggests that VARs monitoring affects match performance, aligning with the principles of the Hawthorne effect. However, no significant differences were observed for variables, such as corners, shots, passes, and yellow cards. 4.1 The impact of VARs monitoring on scoring performance Matches with VARs monitoring showed significantly fewer goals and penalties. Goals, as a key indicator affecting the competition outcome [ 31 ] , have been extensively analyzed. Previous studies have conflicting results, the studies reported no significant difference in goal numbers before and after VARs implementation in the CSL [ 21 , 35 ] . On the contrary, the present study revealed that matches without VARs had significantly more goals than when the VARs did not intervene. The reason for this phenomenon is related to the presence of VARs, which has led to more accurate offside calls [ 17 , 36 ] . Offside or offensive fouls being reviewed, it might be related to the reduction of goals. Penalties also showed a significant decline under VARs monitoring. The players’ exaggerated reactions, especially the strikers who deliberately dive into the goal area to increase foul opportunities, can be seen as cheating [ 37 ] . VARs monitoring could influence performance changes in the penalty area. Thus, with cheating behaviors being reduced, the number of penalties was influenced too. The trend in shots was no significant difference, this result may also be related to factors such as tactical style and playing conditions, so it is recommended that the researcher can combine shot type and shot area to analyze the influence of VARs monitoring. According to the laws of VARs, VARs can be used in the decision of goal and penalty. In addition, another research shows that the number of shots could be translated into more effective goals in certain situations [ 38 ] . Thus, it is recommended that coaches can encourage the athletes to shoot in the game and strengthen the percentage of shooting training. 4.2 The impact of VARs monitoring on attacking performance The attacking variables, pass, free kick, and corner showed different trends. Passing was found no significant difference, which is inconsistent with previous findings [ 21 ] . In addition, no significant difference was observed in the corner. This was probably because the laws of passes and the corner have a lower link to the laws for VARs. Another offensive indicator, free kicks, has decreased. The change in the indicator is related to fouls, and the trend is consistent with fouls. In addition, since the application of VARs, FIFA has further promoted the concept of "encouraging offense" and emphasized the fluency of the game, so there may be an influence in the referee's decision of minor fouls, which may also be one of the reasons for the decrease in free kicks. 4.3 The impact of VARs monitoring on defensive performance As a defensive variable, fouls revealed a consistent trend of free kicks, and this finding aligns with previous studies [ 35 , 36 ] . The Hawthorne effect suggests that when players’ performance is being monitored, players may adjust their actions. Due to the fact that the game will continue with a free kick after a foul during the match. After VARs monitor, whether match performance is affected to minimize undesirable outcomes, such as unnecessary fouls in the forward areas [ 24 , 25 , 36 ] . Thus, it is recommended that researchers explore whether there is a difference in the number of free kicks and fouls in different areas after VARs monitoring. Additionally, tackles, which often involved physical contact to possess the ball [ 39 ] and correlated with fouls [ 40 ] , showed a significant decrease. This phenomenon was largely related to psychology; players may have been calmer and avoided impulsive defensive performance due to VARs monitoring. This emotional restraint may also lead to a decrease in the frequency of tackles. Thus, it is proposed that players should pay more attention to their defensive actions in the games, and coaches should strengthen the training of players' emotions, researchers can explore whether the area of fouls was changed or not after VARs were used. For other defensive-related variables, the study found no significant difference in yellow cards, it is consistent with traditional studies [ 14 ] . This phenomenon was largely related to the overall reduction in fouls. Even if a red card is the same as a yellow card, both are less likely in football. The red card has a significant decrease, mainly because red cards are under the review of VARs, so VARs monitoring leads to fewer fouls and also leads to fewer red cards than before. 4.4 Limitations The study compares the matches in which VARs was not applied, and where VARs was present but did not intervene. However, previous research indicates that outcomes can vary across different leagues. Thus, it is suggested that future studies should target more leagues and select more samples to be analyzed. Additionally, in the future, qualitative methods can be used to analyze the psychological state of the players and to explore the impact of VARs on the psychology of the players as well as their sports performance at a deeper level. 5. Conclusions This study, based on the Hawthorne effect, examines the influence of VARs monitoring on match performance. The findings reveal that VARs was used more frequently after its introduction in the Chinese Super League. Although VARs did not directly intervene in all games, its mere presence notably affected match performance, such as goals, penalties, and fouls. Overall, the study suggests that VARs monitoring, like the Hawthorne effect, has a measurable impact on match performance, particularly in defense. Additionally, VARs monitoring aligns with FIFA's initiative to promote attacking play and helps minimize fouls. The study recommends that coaches should enhance training on coordinated passing, encourage shooting, and improve training sessions under video review to mitigate the influence of the Hawthorne effect. Players should attack boldly, manage their emotions, and limit impulsive defensive actions during games. Declarations Funding This research received no external funding. Ethics approval and consent to participate Not applicable Conflict of Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Consent for publication Not applicable Acknowledgments The authors would like to thank the subjects who participated in this study. Data availability Data of analyses are included in the paper. Some datasets supporting the article are available in the Champads. The link to the database: (http://data.champdas.com), and other data are available from the corresponding author on reasonable request. Author Contribution BZ: Writing – original draft. BZ,PD: Writing – review & editing. DQ: Data curation, editing. ML: art & editing. LZ: Supervision, editing References Samuel RD, Galily Y, Hochman G. The “silent” noise: moving forward from bias to noise in football referees’ decision-making. International Journal of Sport and Exercise Psychology. 2025:1-26. Lex H, Pizzera A, Kurtes M, Schack T. Influence of players' vocalisations on soccer referees' decisions. European Journal of Sport Science. 2015;15(5):424-8. doi: https://doi.org/10.1080/17461391.2014.962620. Sors F, Grassi M, Agostini T, Murgia M. The sound of silence in association football: Home advantage and referee bias decrease in matches played without spectators. European Journal of Sport Science. 2021;21(12):1597-605. doi: https ://doi.org/10.1080/17461391.2020.1845814. Ali MH, Lepretre P-M, Yonis SM, Cozette M, Ballah Y, Ahmaidi S. Analysis of the physical performance and decision-making of football referees in hot and humid environments. American Journal of Sports Science. 2022;10 (3):46-51. Pizzera A, Laborde S, Lahey J, Wahl P. Influence of physical and psychological stress on decision-making performance of soccer referees. Journal of Sports Sciences. 2022;40(18):2037-46. doi:https://doi.org/10.1080/02640 414.2022.2127516. Fédération Internationale de Football Association (FIFA): FAQ: Experiments with video assistant referees in football.https://digitalhub.fifa.com/m/4f07dcacb1af0da/original/gh2ynueyxibiu3vopqax-pdf.pdf(2016). Fédération Internationale de Football Association :refereeing at FWWC.https://digitalhub.fifa.com/m/76b 6efaab152b522/original/zeghumlzve8t7pppcw8m-pdf.pdf(2019). Accessed. International Football Association Board: Video AssistantReferees (VARs) experiment – Protocol (Summary). https://static-3eb8.kxcdn.com/documents/639/165902_220118_IFAB_Media_Package_ABM2017_all_media_ FINAL.pdf (2017). Accessed May 2020. Abbate C, Cross J, Uhrig R. Video assistant referee and home field advantage: Implications for referee bias. Southern Economic Journal. 2025;91(3):1176-96. doi: https://doi.org/10.1002/soej.12731. Bradley PS, Lago-Peñas C, Rey E, Gomez Diaz A. The effect of high and low percentage ball possession on physical and technical profiles in English FA Premier League soccer matches. Journal of Sports Sciences. 2013;31(12):1261-70. doi: https://doi.org/10.1080/02640414.2013.786185. Lago-Peñas C. The role of situational variables in analysing physical performance in soccer. Journal of Human Kinetics. 2012;35:89. doi: https://doi.org/10.2478/v10078-012-0082-9. Mugglestone C, Morris JG, Saunders B, Sunderland C. Half-time and high-speed running in the second half of soccer. International Journal of Sports Medicine. 2013;34(6):514-9. doi: 10.1055/s-0032-1327647. Kubayi A, Larkin P, Toriola A. The impact of video assistant referee (VAR) on match performance variables at men's FIFA World Cup tournaments. Proceedings of the Institution of Mechanical Engineers Part P-Journal of Sports Engineering and Technology. 2022;236(3):187-91. doi: https://doi.org/10.1177/1754337121997581. Zhang Y, Li D, Gomez-Ruano M-A, Memmert D, Li C, Fu M. The effect of the video assistant referee (VAR) on referees' decisions at FIFA Women's World Cups. Frontiers in Psychology.2022;13.doi:https://doi.org/10.3389/fpsyg. 2022.984367. WANG Wuwei, LU Fei, WU Junqian. The Premier League has added the most hours compared to other leagues. China Sport Science and Technology. 2023;43(03):26-40. doi: 10.16469/j.css.202303003. Spitz J, Wagemans J, Memmert D, Williams AM, Helsen WF. Video assistant referees (VAR): The impact of technology on decision making in association football referees. Journal of Sports Sciences.2021;39(2):147-53. doi: https://doi.org/10.1080/02640414.2020.1809163. Fédération Internationale de Football Association: FIFA world cup russia 2018: Refereeing statistics. https: //fifa-backend.pressfire.net/media/newsletter/FWC18-Refereeing-VAR-Report-Statistics-Finals-Stats.pdf (2018). Fisne M, Bardakci S, Hasaan A. Analysis of perceptions of Turkish fans of video-assistant-referees in elite soccer.South African Journal for Research in Sport Physical Education and Recreation. 2021;43(2):29-45. doi: ://WOS:000704720900003. Winand M, Schneiders C, Merten S, Marlier M. Sports fans and innovation: An analysis of football fans' satisfaction with video assistant refereeing through social identity and argumentative theories. Journal of Business Research. 2021;136:99-109. doi: https://doi.org/10.1016/j.jbusres.2021.07.029. Kolbinger O, Knopp M. Video kills the sentiment exploring fans' reception of the video assistant referee in the English premier league using Twitter data.Plos One .2020;15(12). doi:https://doi.org/10.1371/journal.pone. 0242728. Zhaofang P, Ling Y, Wei G, Changjing Z, Bingnan G, Hongyou L. Influence of the implementation of VAR on the running and technical performance for soccer players in the Chinese Super League. Journal of Physical Education and Sport. 2022;29(02):122-7. doi: https://doi.org/10.16237/j.cnki.cn44-1404/g8.2022.02.010. Vergonis A, Balasas D, Michailidis Y, Metaxas T. The significant role of scoring from set plays in the 2018 FIFA World Cup. Journal of Sports Medicine and Physical Fitness. 2020;61(11):1448-53.doi:https://doi.org/10. 23736/s0022-4707.20.11788-2. Bao R, Han B. The influence of the video assistance refereeon the English Premier League. International Journal of Performance Analysis in Sport. 2024;24(3): 241-50. doi:10.1080/24748668.2023.2291236. Deng P, Zhou R, Song YZ, Zhang LQ, Han B. Once or twice? The effect of different number of video assistant referees intervention. Proceedings of the Institution of Mechanical Engineers Part P-Journal of Sports Engineering and Technology. 2024. doi: 10.1177/17543371241265602. Errekagorri I, Castellano J, Echeazarra I, Lago-Penas C. The effects of the Video assistant referee system (VAR) on the playing time, technical-tactical and physical performance in elite soccer. International Journal of Performance Analysis in Sport. 2020;20(5):808-17. doi: 10.1080/24748668.2020.1788350. Kompier MAJ. The "Hawthorne effect" is a myth, but what keeps the story going? Scandinavian Journal of Work Environment & Health. 2006;32(5):402-12. doi: 10.5271/sjweh.1036. Liu H, Yi Q, Giménez J-V, Gómez M-A, Lago-Peñas C. Performance profiles of football teams in the UEFA Champions League considering situational efficiency. International Journal of Performance Analysis in Sport. 2015;15(1):371-90. doi: https://doi.org/10.1080/24748668.2015.11868799. Lago-Penas C, Lago-Ballesteros J. Game location and team quality effects on performance profiles in professional soccer. Journal of Sports Science and Medicine. 2011;10(3):465-71. Aquino R, Martins GHM, Vieira LHP, Menezes RP. Influence of match location, quality of opponents, and match status on movement patterns in Brazilian professional football players. Journal of Strength and Conditioning Research. 2017;31(8):2155-61. doi: https://doi.org/10.1519/JSC.0000000000001674. Castellano J, Álvarez D, Figueira B, Coutinho D, Sampaio J. Identifying the effects from the quality of opposition in a football team positioning strategy. International Journal of Performance Analysis in Sport. 2013;13(3):822-32. doi: https://doi.org/10.1080/24748668.2013.11868691. Lago-Penas C, Lago-Ballesteros J, Dellal A, Gomez M. Game-related statistics that discriminated winning, drawing and losing teams from the Spanish soccer league. Journal of Sports Science and Medicine. 2010;9(2):288-93. Chunman Li, Dong W, Gong b, Li X, Gao S.Depth analysis on the performance of chinese men’s national football team in the 17th asian football cup.China Sport Science and Technology. 2020;56(04):20-8. doi:10.16470/j.csst.201 9056. Gong BN, Cui YX, Gai Y, Yi Q, Gomez MA. The validity and reliability of live football match statistics from champdas master match analysis system. Frontiers in Psychology. 2019;10. doi: 10.3389/fpsyg.2019.01339. Hopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Medicine and Science in Sports and Exercise. 2009;41(1):3-13.doi:10.1249/MSS.0b013e31818c b278. Han B, Chen Q, Lago-Penas C, Wang C, Liu T. The influence of the video assistant referee on the chinese super league. International Journal of Sports Science & Coaching. 2020;15(5-6):662-8.doi:https://doi.org/10.1177/17479 54120938984. Carlos LP, Ezequiel R, Anton K. How does Video assistant referee (VAR) modify the game in elite soccer? International Journal of Performance Analysis in Sport. 2019;19(4):646-53. doi:https://doi.org/10.1080/24748668. 2019.1646521. Sabag E, Lidor R, Morgulev E, Arnon M, Azar O, Bar-Eli M. To dive or not to dive in the penalty area? The questionable art of deception in soccer. International Journal of Sport and Exercise Psychology. 2020;18(3):296-307. doi: https://doi.org/10.1080/1612197X.2018.1462100. Lucey P, Oliver D, Carr P, Roth J, Matthews I. Assessing team strategy using spatiotemporal data. Proceedings of the 19th ACM SIGKDD international conference on Knowledge discovery and data mining. 2013. p. 1366-74. Fuller C, Smith G, Junge A, Dvorak J. The influence of tackle parameters on the propensity for injury in international football. The American Journal of Sports Medicine. 2004;32(1_suppl):43-53. doi:https://doi.org/10.11 77/0363546503261248. Soares JT, Shamir L. Quantitative analysis of penalty kicks and yellow card referee decisions in soccer. American Journal of Sports Science. 2016;4(5):84. doi: https://doi.org/10.11648/j.ajss.20160405.12. Additional Declarations No competing interests reported. Supplementary Files ComparedtoWithoutVideoAssistantRefereeDoesVideoAssistantRefereeMonitoringHaveanImpactontheChineseSuperLeague.docx Cite Share Download PDF Status: Published Journal Publication published 29 May, 2025 Read the published version in BMC Sports Science, Medicine and Rehabilitation → Version 1 posted Editorial decision: Revision requested 28 Apr, 2025 Reviews received at journal 26 Apr, 2025 Reviewers agreed at journal 21 Apr, 2025 Reviewers invited by journal 09 Apr, 2025 Submission checks completed at journal 07 Apr, 2025 First submitted to journal 05 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5663513","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":441008565,"identity":"bd6a98f1-b950-4e50-82fc-ec525c467644","order_by":0,"name":"Bo Zhang","email":"","orcid":"","institution":"China Football College, Beijing Sport University","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Zhang","suffix":""},{"id":441008567,"identity":"aace622e-47e6-4bf9-b246-49b41b57309f","order_by":1,"name":"Mingyuan Lin","email":"","orcid":"","institution":"China Football College, Beijing Sport University","correspondingAuthor":false,"prefix":"","firstName":"Mingyuan","middleName":"","lastName":"Lin","suffix":""},{"id":441008568,"identity":"b90d9124-a8b0-45dd-baed-2243db829c6a","order_by":2,"name":"Delihai Qi","email":"","orcid":"","institution":"Sports Coaching College, Beijing Sport University","correspondingAuthor":false,"prefix":"","firstName":"Delihai","middleName":"","lastName":"Qi","suffix":""},{"id":441008570,"identity":"522f66e8-a7ce-46dd-a7d1-1aea44bd51f7","order_by":3,"name":"Liqing Zhang","email":"","orcid":"","institution":"Sports Coaching College, Beijing Sport University","correspondingAuthor":false,"prefix":"","firstName":"Liqing","middleName":"","lastName":"Zhang","suffix":""},{"id":441008575,"identity":"fe8d3f37-edfd-49fb-8ecd-9b929bc6ac1e","order_by":4,"name":"Pei Deng","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIiWNgGAWjYBACewglkcDAwHwAxJAhqMWwAa6FLQHE4CGoxeAAhAYq5zEAMYjQcrz38OuCCos8+Rk5n1/dqLHgYWA/fHQDXi1nzqVZzzgjUWxwI3ebdc4xoMN40tJu4NVyI8fMmLdNInGDRO424xw2oBYJHjP8Wu6/AWr5J5E4f0bOM+Ocf8RoucFj/Ji3QSKx4UYO8+PcNiK0GPbkmDHPOAb0y5lnZsy5fRI8bIT8Ys9+xvhzQU1dnnx78uPPOd/q5PjZDx/DqwUI2KRhDAkwSUA5CDB/hjE+EKF6FIyCUTAKRiAAAJTlSHq1RXyJAAAAAElFTkSuQmCC","orcid":"","institution":"China Football College, Beijing Sport University","correspondingAuthor":true,"prefix":"","firstName":"Pei","middleName":"","lastName":"Deng","suffix":""}],"badges":[],"createdAt":"2024-12-17 16:23:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5663513/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5663513/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13102-025-01192-5","type":"published","date":"2025-05-29T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80421826,"identity":"df48d8d5-d432-4d6d-91cb-fb9cae7ed190","added_by":"auto","created_at":"2025-04-11 19:14:59","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":32437,"visible":true,"origin":"","legend":"\u003cp\u003eThe Mean value and 95% confidence interval in without VARs and introduction of VARs.\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5663513/v1/bbfcb551c1fd297db87c05f2.png"},{"id":83782924,"identity":"85770689-0cfd-4561-8436-c8151053c11d","added_by":"auto","created_at":"2025-06-02 16:08:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":697889,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5663513/v1/1f57dff1-11b3-4ae0-958f-2a0b5d7e9830.pdf"},{"id":80421832,"identity":"8ad3e9fa-a892-4d1c-ba94-22f62288f7b2","added_by":"auto","created_at":"2025-04-11 19:14:59","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":2411377,"visible":true,"origin":"","legend":"","description":"","filename":"ComparedtoWithoutVideoAssistantRefereeDoesVideoAssistantRefereeMonitoringHaveanImpactontheChineseSuperLeague.docx","url":"https://assets-eu.researchsquare.com/files/rs-5663513/v1/882f878f49e7a43f1bc97949.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Compared to Without Video Assistant Referee: Does Video Assistant Referee Monitoring Have an Impact on the Chinese Super League?","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003e \u003cb\u003eSince the laws of the football game have been applied\u003c/b\u003e, referees have used power to guide football games smoothly. However, the limitations of the subject\u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003eand object factors\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e are all detrimental to the fairness and spectacle of football matches. With the development of competitive sports, the demand for fairness in sports has intensified. Football matches have added a series of intelligent devices\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e, such as NFC smart chips, \"earphones\", and goal-line technology, to compensate for the referee's deficiency. For instance, goal-line technology uses sensors and chips to provide precise data, allowing referees to make accurate decisions.\u003c/p\u003e \u003cp\u003eThe implementation of the Video Assistant Referee system (VARs) by the F\u0026eacute;d\u0026eacute;ration Internationale de Football Association (FIFA) represents another technological advancement aimed at reducing the impact of human error. In matches, at least one video assistant referee (VAR), an assisting VAR (AVAR), and a replay operator (RO) are present in the Video operation room (VOR) to help the referee in the field to decision-making by viewing video\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Since its formal introduction at the 2018 FIFA World Cup\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e, VARs has been introduced in numerous national leagues, including in Spain, France, and China\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNumerous studies have highlighted many situational variables, such as game location\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e, quality of opposition\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e, and match time\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e, influencing players\u0026rsquo; performance. With the application of VARs, many scholars have researched the impacts of VARs on different aspects of the game. Regarding football match time, the study\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e has shown that the time in the matches before and after the implementation of VARs has been increased. This result was also shown in the Women's World Cup\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. For the Chinese Super League (CSL), the introduction of VARs led to an average increase of 2.39 minutes in effective playing time per game\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. About the referee, VARs has improved decision accuracy, as evidenced by a rise in the referee accuracy rate from 92.1\u0026ndash;98.3% in 13 national leagues\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e, and the World Cup in Russia data also shows increased accuracy\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Research on fans\u003csup\u003e[\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e, some studies found that fans viewed VARs as enhancing competitiveness and reducing pressure on referees\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. In contrast, another research\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e observed that loyal fans are more positive about VARs introduction and are especially happy when a judgment is changed in favor of an opposing player. However, fans\u0026rsquo; sentiments towards VARs are more skewed towards the negative by analyzing data from Twitter\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. Concerning athletes, studies have shown that the intervention of VARs can impact athletes' performance, including high-speed running distance\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e, goals\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e, offside\u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e, fouls\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e, and distance of low-speed running\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. Moreover, much research\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003eanalyzed the effect of different numbers of interventions in a football match. While much research has focused on comparing matches with and without VARs interventions, no study has yet analyzed whether the mere presence of VARs monitoring affects player performance. This gap in the literature forms the basis of the study.\u003c/p\u003e \u003cp\u003eBased on numerous studies, the introduction of VARs influence extends beyond the referees, potentially affecting match performance. The Hawthorne effect highlights how human behavior can change when individuals are aware they are being observed\u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e. The discovery of the Hawthorne effect originated from the Hawthorne Factory Experiment, which challenged traditional studies and introduced new perspectives from psychology and sociology. In football games, although VARs doesn't intervene, players remain aware of the camera surveillance on the field. Whether the VARs has the same effect as the Hawthorne effect?\u003c/p\u003e \u003cp\u003eThus, building on the question and previous studies, the study compares the data from matches where VARs did not intervene (2018\u0026ndash;2021 season) with those from the 2014\u0026ndash;2017 seasons (without VARs). This study aims to explore whether the mere presence of VARs monitoring (without actual intervention) has an impact on match performance. Analyzing these performance changes offers valuable insights for football coaches, players, and other management, helping them understand how VARs influences the development of the game.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1Match Sample\u003c/h2\u003e \u003cp\u003eIn the research, VARs non-intervention was defined as the use of VARs not resulting in a significant stoppage of games in the 2018\u0026ndash;2021 season. The CSL in the 2014\u0026ndash;2021 seasons (2014\u0026ndash;2019 season, n\u0026thinsp;=\u0026thinsp;240; 2020 season, n\u0026thinsp;=\u0026thinsp;180; 2021 season, n\u0026thinsp;=\u0026thinsp;176) has 1,796 matches. VARs intervened in a total of 552 matches in the 2018\u0026ndash;2021 season, and VARs did not intervene in 264 matches. A lot of research shows that some contextual information, including game outcome\u003csup\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e, game location\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e, and quality of opposition\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e influence the performance. Thus, situational variables of seasons, game location, quality of opposition and team was taken into account.1224 matches were divided into two groups: VAR-pre (without VARs, n\u0026thinsp;=\u0026thinsp;1920), and VAR-post (VARs did not intervene in a match, n\u0026thinsp;=\u0026thinsp;528). Referring to previous studies, the variables of match performance analyzed for each match included goals, penalties, shots, passes, free kicks, corners, tackles, fouls, yellow cards, and red cards. Based on other research \u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e, the variables were divided into scoring (goal, shot, penalties), attacking (pass, free kick, corner), and defensive variables (tackles, fouls, yellow cards, and red cards).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Procedures\u003c/h2\u003e \u003cp\u003eAll 816 matches in the 2018\u0026ndash;2021 seasons were recorded by downloading video footage from Chinese match broadcasting platforms. The data of VARs intervention was collected by two observers, 20 matches were randomly selected for the study and the two observers made a duplicate collection and the data was tested for reliability. The calculation results showed that the Kappa value of reliability was 0.97. Then, the data of the matches without VARs intervention recording was collected by a single observer. The performance data analyzed in this study were primarily sourced from Creative Ice DATA (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://data.champdas.com\u003c/span\u003e\u003cspan address=\"http://data.champdas.com\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e), where the reliability of the data has been verified by previous scholarly research\u003csup\u003e[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3Analysis\u003c/h2\u003e \u003cp\u003eDescriptive statistics, including the mean and standard deviation, were calculated for the variables used in this study. The 95% confidence intervals of effects were calculated in Microsoft Excel 2007. In addition, the Generalized Linear Mixed Model was employed, with a significance threshold set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Separate Poisson and Negative Binomial were run in the model. A fixed effect for VARs was used, the random effects estimated the effect of the game location, as well as the effect of season, team and opposition strength. The game location was with two levels (home, and away). The season was with eight levels. The effect of team and opponent strength was estimated by the end-of-season points. The thresholds of Cohen\u0026rsquo;s d for small, moderate, large, very large, and extremely large were 0.2, 0.6,1.2, 2.0, and 4.0\u003csup\u003e[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/sup\u003e, and GraphPad was employed for creating the graphical representations in the paper.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003eThe research aimed to investigate the impact of VARs and analyzed the matches in which VARs did not intervene in the 2018\u0026ndash;2021 season through the video observation method. The study found that VARs intervened in 552 matches, with just 264 matches in which the system did not intervene. The percentage of non-intervention was 32 percent.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe results of the Generalized Linear Mixed Model (N\u0026thinsp;=\u0026thinsp;2448)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVAR-pre\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVAR-post\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eF\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eCohen's d\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGoals\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.41\u0026thinsp;\u0026plusmn;\u0026thinsp;6.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.19\u0026thinsp;\u0026plusmn;\u0026thinsp;3.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.01**\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePenalties\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e45.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.001***\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShots\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e12.36\u0026thinsp;\u0026plusmn;\u0026thinsp;37.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.54\u0026thinsp;\u0026plusmn;\u0026thinsp;19.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.602\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.107\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePasses\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e386.84\u0026thinsp;\u0026plusmn;\u0026thinsp;547.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e403.29\u0026thinsp;\u0026plusmn;\u0026thinsp;287.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e-0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFree Kicks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e17.97\u0026thinsp;\u0026plusmn;\u0026thinsp;13.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.63\u0026thinsp;\u0026plusmn;\u0026thinsp;7.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.422\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.001***\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorners\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e4.71\u0026thinsp;\u0026plusmn;\u0026thinsp;15.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.79\u0026thinsp;\u0026plusmn;\u0026thinsp;8.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.164\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e-0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.686\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTackles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e17.01\u0026thinsp;\u0026plusmn;\u0026thinsp;13.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.41\u0026thinsp;\u0026plusmn;\u0026thinsp;7.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.003**\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFouls\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e15.62\u0026thinsp;\u0026plusmn;\u0026thinsp;13.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e14.31\u0026thinsp;\u0026plusmn;\u0026thinsp;7.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.006**\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYellow Cards\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.91\u0026thinsp;\u0026plusmn;\u0026thinsp;5.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.84\u0026thinsp;\u0026plusmn;\u0026thinsp;32.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.449\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRed Cards\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.001***\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eNote. Significant level: ** P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, *** P\u0026thinsp;\u0026lt;\u0026thinsp;0.0001\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAs can be seen in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, a significant difference (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) was found in the scoring variables of goals, and penalties. There was a significant decrease in goals [ (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.04], penalty kicks [\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.07], However, there was no significant difference in the number of shots (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eThe attacking variable of free kicks was obviously different (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). A significant decrease was shown in free kicks [(\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.18]. However, there was no significant difference in the number of passes and corners (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eAnd the defense-related variables of fouls, tackles and red cards have significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), tackles [(\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.13], fouls [\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.11] and red cards [\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, VAR-pre\u0026thinsp;\u0026gt;\u0026thinsp;VAR-post, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.04] showed a significant decreased. While there was no significant difference in the number of yellow cards between the two groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eFrom Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, the effect size of all significant variables shows a small effect.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study investigates whether the mere presence of VARs monitoring, even without intervention, influences match performance. The research uncovered that VARs intervened more times in the CSL, only 32% of the matches in which VARs did not cause a significant pause in the game. In addition, the results indicate that performance indicators, including goals, penalties, fouls, free kicks, and red cards exhibited significant differences. It suggests that VARs monitoring affects match performance, aligning with the principles of the Hawthorne effect. However, no significant differences were observed for variables, such as corners, shots, passes, and yellow cards.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e4.1 The impact of VARs monitoring on scoring performance\u003c/h2\u003e \u003cp\u003eMatches with VARs monitoring showed significantly fewer goals and penalties. Goals, as a key indicator affecting the competition outcome\u003csup\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e, have been extensively analyzed. Previous studies have conflicting results, the studies reported no significant difference in goal numbers before and after VARs implementation in the CSL\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e. On the contrary, the present study revealed that matches without VARs had significantly more goals than when the VARs did not intervene. The reason for this phenomenon is related to the presence of VARs, which has led to more accurate offside calls\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Offside or offensive fouls being reviewed, it might be related to the reduction of goals.\u003c/p\u003e \u003cp\u003ePenalties also showed a significant decline under VARs monitoring. The players\u0026rsquo; exaggerated reactions, especially the strikers who deliberately dive into the goal area to increase foul opportunities, can be seen as cheating\u003csup\u003e[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/sup\u003e. VARs monitoring could influence performance changes in the penalty area. Thus, with cheating behaviors being reduced, the number of penalties was influenced too.\u003c/p\u003e \u003cp\u003eThe trend in shots was no significant difference, this result may also be related to factors such as tactical style and playing conditions, so it is recommended that the researcher can combine shot type and shot area to analyze the influence of VARs monitoring. According to the laws of VARs, VARs can be used in the decision of goal and penalty. In addition, another research shows that the number of shots could be translated into more effective goals in certain situations\u003csup\u003e[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/sup\u003e. Thus, it is recommended that coaches can encourage the athletes to shoot in the game and strengthen the percentage of shooting training.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e4.2 The impact of VARs monitoring on attacking performance\u003c/h2\u003e \u003cp\u003eThe attacking variables, pass, free kick, and corner showed different trends. Passing was found no significant difference, which is inconsistent with previous findings\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. In addition, no significant difference was observed in the corner. This was probably because the laws of passes and the corner have a lower link to the laws for VARs.\u003c/p\u003e \u003cp\u003eAnother offensive indicator, free kicks, has decreased. The change in the indicator is related to fouls, and the trend is consistent with fouls. In addition, since the application of VARs, FIFA has further promoted the concept of \"encouraging offense\" and emphasized the fluency of the game, so there may be an influence in the referee's decision of minor fouls, which may also be one of the reasons for the decrease in free kicks.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e4.3 The impact of VARs monitoring on defensive performance\u003c/h2\u003e \u003cp\u003eAs a defensive variable, fouls revealed a consistent trend of free kicks, and this finding aligns with previous studies\u003csup\u003e[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. The Hawthorne effect suggests that when players\u0026rsquo; performance is being monitored, players may adjust their actions. Due to the fact that the game will continue with a free kick after a foul during the match. After VARs monitor, whether match performance is affected to minimize undesirable outcomes, such as unnecessary fouls in the forward areas\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Thus, it is recommended that researchers explore whether there is a difference in the number of free kicks and fouls in different areas after VARs monitoring.\u003c/p\u003e \u003cp\u003eAdditionally, tackles, which often involved physical contact to possess the ball\u003csup\u003e[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/sup\u003e and correlated with fouls\u003csup\u003e[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/sup\u003e, showed a significant decrease. This phenomenon was largely related to psychology; players may have been calmer and avoided impulsive defensive performance due to VARs monitoring. This emotional restraint may also lead to a decrease in the frequency of tackles. Thus, it is proposed that players should pay more attention to their defensive actions in the games, and coaches should strengthen the training of players' emotions, researchers can explore whether the area of fouls was changed or not after VARs were used.\u003c/p\u003e \u003cp\u003eFor other defensive-related variables, the study found no significant difference in yellow cards, it is consistent with traditional studies\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. This phenomenon was largely related to the overall reduction in fouls. Even if a red card is the same as a yellow card, both are less likely in football. The red card has a significant decrease, mainly because red cards are under the review of VARs, so VARs monitoring leads to fewer fouls and also leads to fewer red cards than before.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Limitations\u003c/h2\u003e \u003cp\u003eThe study compares the matches in which VARs was not applied, and where VARs was present but did not intervene. However, previous research indicates that outcomes can vary across different leagues. Thus, it is suggested that future studies should target more leagues and select more samples to be analyzed. Additionally, in the future, qualitative methods can be used to analyze the psychological state of the players and to explore the impact of VARs on the psychology of the players as well as their sports performance at a deeper level.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis study, based on the Hawthorne effect, examines the influence of VARs monitoring on match performance. The findings reveal that VARs was used more frequently after its introduction in the Chinese Super League. Although VARs did not directly intervene in all games, its mere presence notably affected match performance, such as goals, penalties, and fouls. Overall, the study suggests that VARs monitoring, like the Hawthorne effect, has a measurable impact on match performance, particularly in defense. Additionally, VARs monitoring aligns with FIFA's initiative to promote attacking play and helps minimize fouls. The study recommends that coaches should enhance training on coordinated passing, encourage shooting, and improve training sessions under video review to mitigate the influence of the Hawthorne effect. Players should attack boldly, manage their emotions, and limit impulsive defensive actions during games.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank the subjects who participated in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData of analyses are included in the paper. Some datasets supporting the article are available in the Champads. The link to the database: (http://data.champdas.com), and other data are available from the corresponding author on reasonable request.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eBZ: Writing \u0026ndash; original draft. BZ,PD: Writing \u0026ndash; review \u0026amp; editing. DQ: Data curation, editing. ML: art \u0026amp; editing. LZ: Supervision, editing\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSamuel RD, Galily Y, Hochman G. The \u0026ldquo;silent\u0026rdquo; noise: moving forward from bias to noise in football referees\u0026rsquo; decision-making. International Journal of Sport and Exercise Psychology. 2025:1-26. \u003c/li\u003e\n\u003cli\u003eLex H, Pizzera A, Kurtes M, Schack T. Influence of players\u0026apos; vocalisations on soccer referees\u0026apos; decisions. European Journal of Sport Science. 2015;15(5):424-8. doi: https://doi.org/10.1080/17461391.2014.962620.\u003c/li\u003e\n\u003cli\u003eSors F, Grassi M, Agostini T, Murgia M. The sound of silence in association football: Home advantage and referee bias decrease in matches played without spectators. European Journal of Sport Science. 2021;21(12):1597-605. doi: https ://doi.org/10.1080/17461391.2020.1845814.\u003c/li\u003e\n\u003cli\u003eAli MH, Lepretre P-M, Yonis SM, Cozette M, Ballah Y, Ahmaidi S. Analysis of the physical performance and decision-making of football referees in hot and humid environments. American Journal of Sports Science. 2022;10 (3):46-51. \u003c/li\u003e\n\u003cli\u003ePizzera A, Laborde S, Lahey J, Wahl P. Influence of physical and psychological stress on decision-making performance of soccer referees. Journal of Sports Sciences. 2022;40(18):2037-46. doi:https://doi.org/10.1080/02640 414.2022.2127516.\u003c/li\u003e\n\u003cli\u003eF\u0026eacute;d\u0026eacute;ration Internationale de Football Association (FIFA): FAQ: Experiments with video assistant referees in football.https://digitalhub.fifa.com/m/4f07dcacb1af0da/original/gh2ynueyxibiu3vopqax-pdf.pdf(2016).\u003c/li\u003e\n\u003cli\u003eF\u0026eacute;d\u0026eacute;ration Internationale de Football Association :refereeing at FWWC.https://digitalhub.fifa.com/m/76b 6efaab152b522/original/zeghumlzve8t7pppcw8m-pdf.pdf(2019). Accessed.\u003c/li\u003e\n\u003cli\u003eInternational Football Association Board: Video AssistantReferees (VARs) experiment \u0026ndash; Protocol (Summary). https://static-3eb8.kxcdn.com/documents/639/165902_220118_IFAB_Media_Package_ABM2017_all_media_ FINAL.pdf (2017). Accessed May 2020.\u003c/li\u003e\n\u003cli\u003eAbbate C, Cross J, Uhrig R. Video assistant referee and home field advantage: Implications for referee bias. Southern Economic Journal. 2025;91(3):1176-96. doi: https://doi.org/10.1002/soej.12731.\u003c/li\u003e\n\u003cli\u003eBradley PS, Lago-Pe\u0026ntilde;as C, Rey E, Gomez Diaz A. The effect of high and low percentage ball possession on physical and technical profiles in English FA Premier League soccer matches. Journal of Sports Sciences. 2013;31(12):1261-70. doi: https://doi.org/10.1080/02640414.2013.786185.\u003c/li\u003e\n\u003cli\u003eLago-Pe\u0026ntilde;as C. The role of situational variables in analysing physical performance in soccer. Journal of Human Kinetics. 2012;35:89. doi: https://doi.org/10.2478/v10078-012-0082-9.\u003c/li\u003e\n\u003cli\u003eMugglestone C, Morris JG, Saunders B, Sunderland C. Half-time and high-speed running in the second half of soccer. International Journal of Sports Medicine. 2013;34(6):514-9. doi: 10.1055/s-0032-1327647.\u003c/li\u003e\n\u003cli\u003eKubayi A, Larkin P, Toriola A. The impact of video assistant referee (VAR) on match performance variables at men\u0026apos;s FIFA World Cup tournaments. Proceedings of the Institution of Mechanical Engineers Part P-Journal of Sports Engineering and Technology. 2022;236(3):187-91. doi: https://doi.org/10.1177/1754337121997581.\u003c/li\u003e\n\u003cli\u003eZhang Y, Li D, Gomez-Ruano M-A, Memmert D, Li C, Fu M. The effect of the video assistant referee (VAR) on referees\u0026apos; decisions at FIFA Women\u0026apos;s World Cups. Frontiers in Psychology.2022;13.doi:https://doi.org/10.3389/fpsyg. 2022.984367.\u003c/li\u003e\n\u003cli\u003eWANG Wuwei, LU Fei, WU Junqian. The Premier League has added the most hours compared to other leagues. China Sport Science and Technology. 2023;43(03):26-40. doi: 10.16469/j.css.202303003.\u003c/li\u003e\n\u003cli\u003eSpitz J, Wagemans J, Memmert D, Williams AM, Helsen WF. Video assistant referees (VAR): The impact of technology on decision making in association football referees. Journal of Sports Sciences.2021;39(2):147-53. doi: https://doi.org/10.1080/02640414.2020.1809163.\u003c/li\u003e\n\u003cli\u003eF\u0026eacute;d\u0026eacute;ration Internationale de Football Association: FIFA world cup russia 2018: Refereeing statistics. https: //fifa-backend.pressfire.net/media/newsletter/FWC18-Refereeing-VAR-Report-Statistics-Finals-Stats.pdf (2018).\u003c/li\u003e\n\u003cli\u003eFisne M, Bardakci S, Hasaan A. Analysis of perceptions of Turkish fans of video-assistant-referees in elite soccer.South African Journal for Research in Sport Physical Education and Recreation. 2021;43(2):29-45. doi: \u0026lt;Go to ISI\u0026gt; ://WOS:000704720900003.\u003c/li\u003e\n\u003cli\u003eWinand M, Schneiders C, Merten S, Marlier M. Sports fans and innovation: An analysis of football fans\u0026apos; satisfaction with video assistant refereeing through social identity and argumentative theories. Journal of Business Research. 2021;136:99-109. doi: https://doi.org/10.1016/j.jbusres.2021.07.029.\u003c/li\u003e\n\u003cli\u003eKolbinger O, Knopp M. Video kills the sentiment exploring fans\u0026apos; reception of the video assistant referee in the English premier league using Twitter data.Plos One .2020;15(12). doi:https://doi.org/10.1371/journal.pone. 0242728.\u003c/li\u003e\n\u003cli\u003eZhaofang P, Ling Y, Wei G, Changjing Z, Bingnan G, Hongyou L. Influence of the implementation of VAR on the running and technical performance for soccer players in the Chinese Super League. Journal of Physical Education and Sport. 2022;29(02):122-7. doi: https://doi.org/10.16237/j.cnki.cn44-1404/g8.2022.02.010.\u003c/li\u003e\n\u003cli\u003eVergonis A, Balasas D, Michailidis Y, Metaxas T. The significant role of scoring from set plays in the 2018 FIFA World Cup. Journal of Sports Medicine and Physical Fitness. 2020;61(11):1448-53.doi:https://doi.org/10. 23736/s0022-4707.20.11788-2.\u003c/li\u003e\n\u003cli\u003eBao R, Han B. The influence of the video assistance refereeon the English Premier League. International Journal of Performance Analysis in Sport. 2024;24(3): 241-50. doi:10.1080/24748668.2023.2291236.\u003c/li\u003e\n\u003cli\u003eDeng P, Zhou R, Song YZ, Zhang LQ, Han B. Once or twice? The effect of different number of video assistant referees intervention. Proceedings of the Institution of Mechanical Engineers Part P-Journal of Sports Engineering and Technology. 2024. doi: 10.1177/17543371241265602.\u003c/li\u003e\n\u003cli\u003eErrekagorri I, Castellano J, Echeazarra I, Lago-Penas C. The effects of the Video assistant referee system (VAR) on the playing time, technical-tactical and physical performance in elite soccer. International Journal of Performance Analysis in Sport. 2020;20(5):808-17. doi: 10.1080/24748668.2020.1788350.\u003c/li\u003e\n\u003cli\u003eKompier MAJ. The \u0026quot;Hawthorne effect\u0026quot; is a myth, but what keeps the story going? Scandinavian Journal of Work Environment \u0026amp; Health. 2006;32(5):402-12. doi: 10.5271/sjweh.1036.\u003c/li\u003e\n\u003cli\u003eLiu H, Yi Q, Gim\u0026eacute;nez J-V, G\u0026oacute;mez M-A, Lago-Pe\u0026ntilde;as C. Performance profiles of football teams in the UEFA Champions League considering situational efficiency. International Journal of Performance Analysis in Sport. 2015;15(1):371-90. doi: https://doi.org/10.1080/24748668.2015.11868799.\u003c/li\u003e\n\u003cli\u003eLago-Penas C, Lago-Ballesteros J. Game location and team quality effects on performance profiles in professional soccer. Journal of Sports Science and Medicine. 2011;10(3):465-71. \u003c/li\u003e\n\u003cli\u003eAquino R, Martins GHM, Vieira LHP, Menezes RP. Influence of match location, quality of opponents, and match status on movement patterns in Brazilian professional football players. Journal of Strength and Conditioning Research. 2017;31(8):2155-61. doi: https://doi.org/10.1519/JSC.0000000000001674.\u003c/li\u003e\n\u003cli\u003eCastellano J, \u0026Aacute;lvarez D, Figueira B, Coutinho D, Sampaio J. Identifying the effects from the quality of opposition in a football team positioning strategy. International Journal of Performance Analysis in Sport. 2013;13(3):822-32. doi: https://doi.org/10.1080/24748668.2013.11868691.\u003c/li\u003e\n\u003cli\u003eLago-Penas C, Lago-Ballesteros J, Dellal A, Gomez M. Game-related statistics that discriminated winning, drawing and losing teams from the Spanish soccer league. Journal of Sports Science and Medicine. 2010;9(2):288-93. \u003c/li\u003e\n\u003cli\u003eChunman Li, Dong W, Gong b, Li X, Gao S.Depth analysis on the performance of chinese men\u0026rsquo;s national football team in the 17th asian football cup.China Sport Science and Technology. 2020;56(04):20-8. doi:10.16470/j.csst.201 9056.\u003c/li\u003e\n\u003cli\u003eGong BN, Cui YX, Gai Y, Yi Q, Gomez MA. The validity and reliability of live football match statistics from champdas master match analysis system. Frontiers in Psychology. 2019;10. doi: 10.3389/fpsyg.2019.01339.\u003c/li\u003e\n\u003cli\u003eHopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Medicine and Science in Sports and Exercise. 2009;41(1):3-13.doi:10.1249/MSS.0b013e31818c b278.\u003c/li\u003e\n\u003cli\u003eHan B, Chen Q, Lago-Penas C, Wang C, Liu T. The influence of the video assistant referee on the chinese super league. International Journal of Sports Science \u0026amp; Coaching. 2020;15(5-6):662-8.doi:https://doi.org/10.1177/17479 54120938984.\u003c/li\u003e\n\u003cli\u003eCarlos LP, Ezequiel R, Anton K. How does Video assistant referee (VAR) modify the game in elite soccer? International Journal of Performance Analysis in Sport. 2019;19(4):646-53. doi:https://doi.org/10.1080/24748668. 2019.1646521.\u003c/li\u003e\n\u003cli\u003eSabag E, Lidor R, Morgulev E, Arnon M, Azar O, Bar-Eli M. To dive or not to dive in the penalty area? The questionable art of deception in soccer. International Journal of Sport and Exercise Psychology. 2020;18(3):296-307. doi: https://doi.org/10.1080/1612197X.2018.1462100.\u003c/li\u003e\n\u003cli\u003eLucey P, Oliver D, Carr P, Roth J, Matthews I. Assessing team strategy using spatiotemporal data. Proceedings of the 19th ACM SIGKDD international conference on Knowledge discovery and data mining. 2013. p. 1366-74.\u003c/li\u003e\n\u003cli\u003eFuller C, Smith G, Junge A, Dvorak J. The influence of tackle parameters on the propensity for injury in international football. The American Journal of Sports Medicine. 2004;32(1_suppl):43-53. doi:https://doi.org/10.11 77/0363546503261248.\u003c/li\u003e\n\u003cli\u003eSoares JT, Shamir L. Quantitative analysis of penalty kicks and yellow card referee decisions in soccer. American Journal of Sports Science. 2016;4(5):84. doi: https://doi.org/10.11648/j.ajss.20160405.12.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Video assistant referee, Hawthorne effect, Chinese Super League","lastPublishedDoi":"10.21203/rs.3.rs-5663513/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5663513/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eEven though the Chinese Super League (CSL) introduced Video Assistant Referees (VARs) in the 2018 season, it did not intervene in every game. The Hawthorne effect highlights how human behavior can change when individuals are aware they are being observed. VARs monitoring means VAR just introduces but does not intervene in the games. Thus, this research compared the performance in the games where VARs did not intervene and without VARs, to investigate whether VARs monitoring influences match performance, similar to the Hawthorne effect.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThe sample includes matches in which VARs were not applied in the 2014\u0026ndash;2017 season (n\u0026thinsp;=\u0026thinsp;1920) and in which VARs were not intervened in the 2018\u0026ndash;2021 season (n\u0026thinsp;=\u0026thinsp;528). The Generalized Linear Mixed Model was used to examine the different variables in different groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe study found that after the implementation of VARs in the game, the percentage of non-intervention was 32 percent. Even though VARs was not applied, it had a significant impact on goals (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.04), penalties (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.07), free kicks (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.18), tackles (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.13), fouls (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.11), and red cards (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Cohen\u0026rsquo;s d\u0026thinsp;=\u0026thinsp;0.04). Still, there were no significant differences in the number of shots, passes, corners, and yellow cards (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eIn the CSL, VARs intervenes frequently in matches. VARs monitoring also had a certain degree of impact on sports performance, especially defensive performance. In addition, VARs monitoring follows the idea of FIFA to encourage attacking, and it also benefits limited fouls.\u003c/p\u003e","manuscriptTitle":"Compared to Without Video Assistant Referee: Does Video Assistant Referee Monitoring Have an Impact on the Chinese Super League?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-11 19:14:54","doi":"10.21203/rs.3.rs-5663513/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-28T05:17:15+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-26T13:46:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"12006557159501280351831591576639051509","date":"2025-04-21T10:27:30+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-09T19:55:55+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-08T03:07:24+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Sports Science, Medicine and Rehabilitation","date":"2025-04-05T18:21:07+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"594eed76-c4be-433b-a995-7c4471e2ac3b","owner":[],"postedDate":"April 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-06-02T16:02:24+00:00","versionOfRecord":{"articleIdentity":"rs-5663513","link":"https://doi.org/10.1186/s13102-025-01192-5","journal":{"identity":"bmc-sports-science-medicine-and-rehabilitation","isVorOnly":false,"title":"BMC Sports Science, Medicine and Rehabilitation"},"publishedOn":"2025-05-29 15:57:43","publishedOnDateReadable":"May 29th, 2025"},"versionCreatedAt":"2025-04-11 19:14:54","video":"","vorDoi":"10.1186/s13102-025-01192-5","vorDoiUrl":"https://doi.org/10.1186/s13102-025-01192-5","workflowStages":[]},"version":"v1","identity":"rs-5663513","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5663513","identity":"rs-5663513","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}