Complementary Indicators of Knowledge Purporting and Their Validity

Overclaiming (OC)—the tendency to claim knowledge one does not possess—is predominantly assessed through self-report Overclaiming Questionnaires (OCQs). However, exclusive reliance on OCQs raises concerns about mono-method bias, limiting our understanding of knowledge purporting as a broader psychological disposition. To reduce this bias, we investigated two additional indicators of knowledge purporting and examined their convergent validity with traditional OCQs. In our study (N = 301), one of the new measures scored responses on fictional questions (e.g., responding to entirely fabricated historical events) and the other captured discrepancies between self-rated knowledge and actual knowledge provided by participants. Using latent variable analyses, we found modest convergent relations between OC as measured by an OCQ and the other indicators of knowledge purporting. Apart from these substantial levels of method-specific variance, we found differential relations with covariates, thereby challenging the validity and utility of any specific task class, including the predominantly used OCQs. We recommend that knowledge purporting measures must not be equated with the broader concept of knowledge purporting. While this study suggests that the concept of knowledge purporting may have some generality, it also shows that the methods used to investigate it matter more than they should. Future studies should consider the relationship between multivariate measures of knowledge purporting and further discrepancies between self-reports of knowledge and actual performance.