In this post, I will review studies comparing the predictive validity of cognitive ability and parental socioeconomic status (SES) on academic achievement. Parental SES is usually measured via some combination of parental income, educational attainment, and occupational status. Academic achievement is measured either through grades or achievement test scores. A clear picture emerges from each study cited in this post: cognitive ability is a far superior predictor of academic achievement than is parental SES.