IQ measures something real, and it is associated with certain outcomes. For example, thirteen-year-old children who scored in the top decile of the top percent (99.9th percentile) on the math section of the SAT were eighteen times more likely to earn a doctorate degree in math or science than children who scored in the bottom decile of the top percent (99.1st percentile).
RQ is the ability to think rationally and, as a consequence, to make good decisions. Whereas we generally think of intelligence and rationality as going together, Stanovich’s work shows that the correlation coefficient between IQ and RQ is relatively low at .20 to .35. IQ tests are not designed to capture the thinking that leads to judicious decisions.
Stanovich laments that almost all societies are focused on intelligence when the costs of irrational behavior are so high. But you can pick out the signatures of rational thinking if you are alert to them. According to Stanovich, they include adaptive behavioral acts, efficient behavioral regulation, sensible goal prioritization, reflectivity, and the proper treatment of evidence.
Your SAT scores shed little light on any of these qualities. So the first lesson in assessing your own decisions or those of others is to consider IQ and RQ separately. Warren Buffett, chairman and chief executive officer (CEO) of Berkshire Hathaway, equates IQ to the horsepower of an engine and RQ to the output. We all know people who are high on IQ but average or low on RQ. Their efficiency is poor. There are others without dazzling IQs but who consistently make sound decisions. They are highly efficient.