The Incremental Validity of Average States: A Replication and Extension of Finnigan and Vazire (2018)

States refer to our momentary thoughts, feelings, and behaviors. Average states (aggregates across multiple time points) are discussed as a more accurate and objective measure of personality compared to global self-reports since they do not only rely on people’s general beliefs about themselves. Specifically, Finnigan and Vazire (2018) argued that, if average states better capture what a person is actually like, this should be reflected in their unique association with informant-reports of personality, and tested this idea based on two experience-sampling studies. Their results showed, however, that average self-reported states did not predict global informant-reported personality above and beyond global self-reports. In this research, we aimed at replicating and extending these results. We used data of five studies (total N = 806) that involved global self- and informant-reports and employed a variety of different experience-sampling methods (time-based with different sampling schedules, event-based). Across all studies, the original results (i.e., no incremental effects of average self-reported states) were replicated. Furthermore, as an extension to the original study, we found that average other-reported states (provided by peers, results based on one study) did indeed predict global informant-reports above and beyond global self-reports. These findings highlight the importance of differentiating between method effects (global reports vs. average states) from source of information effects (self vs. other). We discuss these results, focusing on the suitability of using informant-reports as a criterion variable and conceptual differences between assessment methods.