I have often read that ability tests are indicative of what people "can do", but that job performance also depends on what people "will do".
For example, Ackerman and Beier (2012) wrote that:
There is a fundamental mismatch between what is measured by extant intelligence tests and the criteria one is most interested in, when predicting job-related performance measures, that is, the mismatch between typical and maximal behaviors. ... Although assessments of what someone can do will serve as an assessment of the upper bound of a person’s performance on the day that the applicant is assessed, I–O psychologists and managers are most interested in what the applicant will do on a day-to-day basis on the job—that is, the individual’s typical performance.
Thus, my questions are:
- What is the correlation between maximal job performance and typical job performance?
- To what extent do ability tests predict maximal performance more than typical performance?
I'm interested in learning about empirical studies that have tested these ideas. I also imagine that findings will vary based on factors related to the work setting, and so forth (e.g., some work environments permit greater variability in discretionary effort). Also, presumably the degree to which ability-performance correlations differ between typical and maximal will be greater where the correlation between typical and maximal is lower. I'm also interested in understanding more about the methodological challenges associated with operationalising typical and maximal performance.
- Ackerman, P. L., Beier, M. (2012) The problem is in the defition: g and intelligence in I-O psychology. Industrial and Organizational Psychology, 5 149–188.