Sure, plenty are smart, or at least not dumb. But the difference doesn&#x27;t even have to be so simple as smart&#x2F;dumb. If your hiring pool consists of two distinct sources, one with an average IQ of 98 (i.e. not dumb), and the other an average IQ of 105, the second source will probably have more hires. Increase the difference (say, to a full standard deviation) and it&#x27;s only worse for the lower group.