When a hiring manager says things like, “I could tell within the first few seconds of the interview…” or “I could tell by the handshake…,” etc., we know they either have not been properly trained on how to hire or simply shouldn’t be in the position of hiring people.
Cognitive ability assessments are among the best predictors of success in the hiring process. Structured interviews and work samples are valuable. Years of experience and education tend not to be predictive. References weren’t predictive in the latest research. But if someone doesn’t believe in data, and overrates their own intuitive powers (as many hiring managers do), then none of this information will make any difference to them.
The seminal study:
Schmidt, F. L., & Hunter, J. E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological bulletin, 124(2), 262.
A newer study shed additional light:
Sackett, P. R., Zhang, C., Berry, C. M., & Lievens, F. (2021). Revisiting meta-analytic estimates of validity in personnel selection: Addressing systematic overcorrection for restriction of range. Journal of Applied Psychology.