Cognitive test scores tell us how quickly a person can learn. They tell us nothing about a person’s integrity, creativity, punctuality, interpersonal style or ability to provide customer service, handle pressure, or work as part of a team. Two large, peer reviewed, meta-analytic studies of leadership report a correlation of .27 between intelligence and leadership, and a correlation of .48 between personality and leadership. In a famous review of over 85 years of selection research, Schmidt and Hunter show that adding a measure of conscientiousness to a measure of cognitive ability improves validity by 18 %; adding a measure of integrity improves validity by 27 %; conversely, adding a measure of cognitive ability to a measure of conscientiousness yields very little increase in validity.

Joyce Hogan, Robert Hogan, and Paul Barrett published an important empirical paper that shows definitively that faking during the job application process is irrelevant for the Hogan Personality Inventory (HPI). The abstract is presented below: “Real job applicants completed a Five-Factor Model personality measure as part of the job application process. They were rejected; six months later they (n = 5, 266) re-applied for the same job and completed the same personality measure. Results indicated that 5.2 % or less improved their scores on any scale on the second occasion; moreover, scale scores were as likely to change in the negative direction as the positive. Only three applicants changed scores on all five scales beyond a 95 % confidence threshold….For the small number of applicants whose scores changed beyond the standard error of measurement, the changes were systematic and predictable using measures of social skill, social desirability, and integrity. Results suggest that faking on personality measures is not a significant problem in real world selection settings.”