“…Three of these studies found that ENDS MLSAs increased teen smoking by approximately 0.8 to 1.0 pp (Dave, Feng, & Pesko, 2019;Friedman, 2015;Pesko, Hughes, & Faisal, 2016), while a fourth study used Monitoring the Future data and found that ENDS MLSAs decreased smoking participation of high school seniors by 2.0 pp (Abouk & Adams, 2017). At least one other study suggests that ENDS are complements with cigarettes, although within a sample of primarily adult cigarette smokers (Cotti, Nesson, & Tefft, 2018). Our study will help shed light on this issue using a longitudinal analysis.…”