Student selection for psychology. Test development and predictive validity

International research in the field of college admission unequivocally demonstrates that achievement and ability tests are adequate predictors of subsequent graduate and undergraduate grade point average and that they are incrementally valid over and above high school grade point average. Nevertheless, German universities rarely use standardized ability and achievement tests for admission purposes. Here we describe the development and validation of a test battery for admission to psychology programs at German universities. In the context of selecting 1,187 applicants for 60 university places, we use regression analysis and structural equation modelling to investigate predictive and incremental validity of the new test battery. In addition to a general factor for reasoning ability, a second, nested factor for relevant prior knowledge can be established as a predictor. Both latent factors contribute substantially to the prediction of undergraduate grade point average. The results clearly support the use of ability and achievement tests for admission to degree programs with more applicants than available places. In addition to reasoning ability, relevant prior knowledge deserves close consideration.