Brian Flaherty’s research has focused on categorical and longitudinal statistical models, measurement and psychometrics, developmental theory and methods, substance use and dependence, and classification and cluster analysis, with particular attention paid to applied statistics in combination with tobacco and other substance use. Specifically, he has been examining the use of categorical latent variable models as measurement models for sub-populations. Within the context of tobacco use, for example, his work has examined how smoking patterns vary across demographic groups, such as age, race and gender. This work is motivated simultaneously by substantive and methodological research questions. He has published on these topics in Drug and Alcohol Dependence, Addiction, American Journal of Public Health and Developmental Psychology.