Summary

Group-based trajectory modeling (GBTM) is a variant of growth mixture modeling that has risen to prominence in the field of criminology as a useful method for understanding heterogeneity in developmental patterns of outcomes of interest. The method entails identification of a trajectory model that best fits a set of longitudinal data and is comprised of a set number of trajectory groups of varying complexity that participants are assigned membership to. Following identification of a best fitting model, extensions of the method can then be used to better understand nuances of the developmental outcome of interest. The use of particular extensions of the method then relies on the research question. These extensions may be used to identify predictors of differential development, understand how differential development predicts a later outcome, or understand how development of another outcome predicts concurrent development of the outcome of interest. While the GBTM method has been demonstrated to have a high degree of utility for modeling criminological outcomes of interest, there remain a number of notable gaps in the manner in which it has been applied in the field.

Given the general shift toward a life-course understanding of criminology, there remain numerous areas where GBTM may be useful for advancing existing criminological theories within this paradigm. While not an exhaustive list, social control theory, social learning theory, general strain theory, and the dual systems model are all examples of criminological theories which may be particularly amenable to the use of GBTM to better understand nuances of development of constructs of interest and advance the perspectives on criminogenic processes that these theories currently offer. These issues indicate the continued need for examination of relationships of interest using GBTM and related extensions of the method within the field of criminology.