Conscientiousness and Job Performance: How Strong Is the Evidence Really?

The Question

Conscientiousness is widely regarded as the personality trait most consistently predictive of job performance. It has been a cornerstone of personality-based selection for decades. Watrin and colleagues (2023) conducted a meta-analytic reality check, asking not just how large the effect is but how well the existing evidence actually supports applying it in real selection contexts.

What They Found

The overall correlation between conscientiousness and job performance was consistent with previous meta-analyses at r = .17 across 102 studies and 23,305 participants (Watrin et al., 2023). This is a modest effect, though not a negligible one in the context of personnel selection.

More importantly, the correlation did not differ meaningfully across validation designs (concurrent versus predictive) or sample types (incumbents versus applicants). On the surface, this looks reassuring: the effect appears stable regardless of how it is studied.

The Critical Problem

The reassurance evaporates when the authors examine who has actually been studied. Only around 12 percent of studies in the literature were conducted with real job applicants in predictive designs (Watrin et al., 2023). The overwhelming majority of research has used incumbent samples, meaning current employees, with personality and performance measured at the same time.

This matters enormously for how the findings should be applied. In real selection contexts, applicants have strong incentives to present themselves favourably, which means self-report personality measures are vulnerable to faking in ways that incumbent studies, where there is no selection pressure, cannot capture. Personality may also change between the point of assessment and the point at which performance is evaluated, particularly for younger workers early in their careers (Watrin et al., 2023).

The practical implication is uncomfortable: almost all of the research used to justify personality-based selection in hiring has been conducted under conditions that do not resemble hiring. The validity of conscientiousness measures in actual applicant samples, where faking is both possible and rational, remains largely an open question (Watrin et al., 2023).

Reference

Watrin, L., Weihrauch, L., & Wilhelm, O. (2023). The criterion-related validity of conscientiousness in personnel selection: A meta-analytic reality check. International Journal of Selection and Assessment. Advance online publication. https://doi.org/10.1111/ijsa.12413