To predict a student’s future success, look at their grades, not their IQ or SAT score

Personality, not raw intelligence, is a better judge of lifetime success, new research shows.

Colleges and employers interested in predicting the success of applicants would do better to look at a student’s grades, which measure personality traits, like grit and attention to detail, more effectively than IQ and SAT tests, according to a recent study from a team led by James Heckman, the Nobel Prize-winning economist from the University of Chicago. The research was released as a discussion paper by the IZA Institute of Labour Economics.

Heckman has spent his career studying how life outcomes are shaped by environment and education, and his groundbreaking research showing the economic benefits of early childhood education was cited by the Obama White House in support of universal pre-K education. This new study may support efforts to stop college admissions from relying on standardized testing, which critics say is racially biased and benefits students who can afford test prep courses. More than 900 US colleges no longer require students to submit the SAT or ACT.

The researchers, from Chicago and Maastricht University in the Netherlands, used data from four studies that tested students and young adults in Europe and the US on grades, IQ, personality, and achievement. Three of the four studies followed the students over a decade or more, and examined how they did on a variety measures of life outcomes, like wages, arrest rates, body mass index, and whether or not they voted. Together, the studies show personality and grades correlate more strongly with later measures of success and happiness than IQ.

For example, in the National Survey of Midlife Development, which researchers at the University of Wisconsin used to study 2,298 Americans over 10 years, the results of a personality test were twice as predictive as IQ on future wages, and four times more predictive of health.

None of the four studies perfectly demonstrates the results—not all measured the same traits, or had other flaws—but together they send a clear signal that grades are very predictive, said John Eric Humphries, a University of Chicago researcher who worked on the study with Heckman.

Employers and colleges have generally preferred standardized tests like the SAT over grade point averages because grades can vary wildly by teacher and school, but GPA reflects other life skills the SAT can’t capture, Humphries says. “It measures your ability to do your school work,” he says. “It measures your knowledge of the material but also things like how well you do at taking tests, going to class, doing homework.”

As scholars isolate what the traits that predict success later in life, the next step is to develop measures that can teach and enhance them in schools, Humphries said. Ultimately, teaching life skills to students may be as important as teaching math and writing.