--- - |2 Increasingly, three generation studies have investigated intergenerational (IG) continuity and discontinuity in substance use and related problem behaviors. However, surprisingly little attention has been paid to the conceptual definition of continuity or to different types of discontinuity (resilience and escalation) or to measurement sensitivity, which affects not only the magnitudes of observed continuity but also factors that correlate with this linkage. This study uses longitudinal data on 427 parent–child dyads from the Rochester IG Study to study continuity and discontinuity in substance use over ages 14–18. Results suggest that the degree of IG continuity, resilience, and escalation in adolescent substance use, as well as correlates of each, depend heavily on how heterogeneity in the behavior is taken into account. - Child Development, Volume 89, Issue 5, Page 1625-1641, September/October 2018.