In any case, both approaches assume that most people follow one of a few distinct trajectories of alcohol use. Between these frequently traversed trajectories are developmental gaps—zones of rarity that enable analytic techniques to identify the common trajectories by contrast. The trajectory group approach is appealing because it simplifies, categorizes, and predicts: data are reduced, individuals are classified, and risk is forecasted. If the trajectory group approach reflects real categorical differences in the population, it is an extremely powerful tool for identifying category members and attuning prevention and intervention strategies.
