A self-determination theory approach to predicting school achievement over time: the unique role of intrinsic motivation

•We test longitudinal relations of different motivation types to school achievement.•Intrinsic motivation is the only consistent predictor of academic achievement across different school contexts and different cultures.•We also find reciprocal relations between achievement and motivation types.

Although many studies have examined the relation of academic motivation to school achievement using the Self-Determination Theory perspective, the results have been inconsistent. The present investigation represents the first systematic attempt to use a meta-analysis and controlled, longitudinal studies to examine the relations of specific types of motivation to overall academic achievement. The meta-analysis (Study 1) pointed toward a potentially important role of intrinsic motivation in predicting school achievement. Three empirical studies of high school and college students in Canada (Studies 2 and 3) and in Sweden (Study 4) showed that intrinsic motivation was the only motivation type to be consistently positively associated with academic achievement over a one-year period, controlling for baseline achievement. Amotivation was significantly associated with lower academic achievement in Studies 3 and 4. Interestingly, intrinsic motivation was also associated with reduced amotivation in two of our studies and it was reciprocally associated with higher school achievement in another study. Overall, our findings highlight the unique importance of intrinsic motivation for the future academic success of high school and college students.