Comparison of longitudinal phenotypes based on alternate heavy drinking cut scores: a systematic comparison of trajectory approaches III.

The goal of the present study was to empirically determine the effect of employing different cut scores for frequency of heavy episodic drinking (HED; an often-used indicator of problematic alcohol involvement) within a longitudinal framework. Using data from a large prospective (9-wave) college student sample, the authors used latent class growth analyses to characterize developmental trajectories of HED based on alternate cut scores that varied in frequency of HED (defined by 5+ drinks per occasion), as well as to measure very heavy episodic drinking (12+ drinks per occasion). As cut score severity increased and base rates for HED correspondingly decreased, individuals were increasingly categorized into less severe classes. Concordance between trajectories ranged from small to moderate, with concordance using highly discrepant definitions of frequent HED being particularly low. HED trajectories based upon different cut scores were validated against a range of etiological and consequential correlates. No single cut score was superior to others in explaining variance in external validity indicators, suggesting that the choice of cut score should be based upon theoretical and clinical considerations. This study further extends the authors' prior work examining the effects of methodological factors that are critical to characterizing the developmental course of alcohol involvement.