New analyses of an old topic: Effects of intelligence and motivation on academic achievement

Abstract

This study focuses on a topic with a long tradition in educational psychology. In a large data set with several achievement measures we investigated the effects of intelligence and motivation on academic achievement in three domains, namely, German, mathematics, and English, using three different achievement measures (standardized tests, grades, and final written exams) in a sample of upper secondary students (N = 3,775; Grade 13; 54.8 % female; age M = 19.92 years) in Germany. Furthermore, we focused on grade point average (GPA) as a general achievement indicator at the end of upper secondary school. First, we aimed to replicate previous results on the predictive power of intelligence and motivation for achievement. Second, we aimed to extend the large body of existing research by adding final written exams - school-based performance tests - as an additional measure. Our findings indicate that motivation had stronger effects on achievement than intelligence did. This was particularly true for the domain-specific achievement measures. Motivation had the strongest effects on grades, followed by final exams. The effects of intelligence were comparatively stronger for standardized achievement tests. Overall, the findings suggest that both intelligence and motivation are important predictors of achievement and that this is true for all kinds of achievement measures.