So much has been written about leadership personality and style that hiring managers are in danger of neglecting the most critical factor in executives’ success: intelligence. More specifically, those responsible for hiring and promoting haven’t been given the tools necessary to evaluate the cognitive abilities that allow a person to consistently reach the “right” answer. How could they recognize such smarts? Historically, the only reliable measure of such brainpower has been the standard IQ test, which, for good reasons, is rarely used in business settings. But in rejecting IQ testing altogether, hiring managers have turned their backs on the single most effective assessment of cognitive abilities, simply because there isn’t a version that applies to the corporate world. They have dismissed the one method that could help them identify business stars.

A version of this article appeared in the November 2005 issue of Harvard Business Review.