ABSTRACT
The study of adolescent development requires that we follow individuals over time, it demands longitudinal designs. Longitudinal research makes it possible to answer a multitude of questions on adolescent development. It allows the detection of the direction of development: do we see certain characteristics or behaviors increase or decrease when adolescents get older; for instance, do conflicts between adolescents and parents decrease over time? Also, it offers the possibility to detect maturation in adolescence: do certain characteristics become more stable within individuals when they get older; for instance, their personality profile? Finally, longitudinal models make it possible to study covariation of various developmental processes over time. For instance, whether parental support goes together with less anxiety in adolescents over time, or even whether parental support leads to decrease of anxiety over time. Since the last decade of the twentieth century, we have witnessed a huge growth in the use of longitudinal models to study adolescent development. This chapter aims to give a conceptual and non-statistical introduction to the most widely used longitudinal models.
