Introduction
influence behaviors
RECRUITMENT
Longitudinal studies allow researchers to monitor behaviors, understand dynamic relationships between different factors that influence behaviors, and establish causation by studying how behaviors evolve over time [High follow-up rates are critical in longitudinal research; missing data can significantly impact the validity and reliability of the findings [Incentive structures can be unconditional, granted regardless of survey participation, or conditional, awarded only upon survey completion [To our knowledge, no studies have examined a hybrid approach in which half of the incentive is unconditional and half is conditional upon valid survey completion. Additionally, there is a lack of research in incentive structures for web-based surveys of US adults who use e-cigarettes, a population that presents recruitment challenges due to lower prevalence. In this case study, we examine participant progress through a survey and resulting participant demographics for 2 incentive delivery structures among a sample of US adults who frequently use e-cigarettes to determine the most effective incentive structure for optimizing survey retention while maintaining representativeness.