The purpose of this thesis is to examine the dynamic development of cognitive and socioemotional traits and how these traits influence academic achievement and predict risk of unemployment. Data was retrieved from the Evaluation Through Following-up (ETF) database. The data consists of 9,080 students born in 1972, who answered a questionnaire and completed cognitive ability tests in 3rd and 6th grade. In addition, register-based data was used for students’ grades and for various background variables. All analyses were conducted using structural equation modelling (SEM). The dynamic development of the relationships between cognitive and socioemotional traits between 3rd and 6th grade is driven by cognitive ability factors. Support was found for Cattell’s investment hypothesis, which states that fluid cognitive ability (Gf) influences development of crystallized cognitive ability (Gc). No influence of socioemotional traits on either cognitive traits or socioemotional traits was found. The evidence of a Gc reading achievement trait complex was weak. Furthermore, both cognitive and socioemotional traits are related to academic achievement. In the prediction of unemployment risk, effects of almost all cognitive and socioemotional traits are captured by grades. Gc has both a direct effect on unemployment risk and an indirect effect via grades on unemployment risk. All other effects of socioemotional traits and Gf are related to the risk of unemployment via academic achievement. The strongest determinant of unemployment risk is academic achievement, which has a protective effect on the risk of unemployment.