Based on self-determination and social exchange theory, this study investigates the effects of extrinsic motivation, intrinsic motivation, and trust in anonymity on enduring survey participation over a period of 2 years. Trust in anonymity was expected to act as a moderator between motivations and the likelihood of repeated survey participation. Participants were N = 227 adolescent members of an academic online panel for youth research. Results of longitudinal logistic regression analyses demonstrated a steady decline in the probability of survey participation over time. Extrinsic but not intrinsic motivation significantly increased the probability of initial survey participation, whereas both, extrinsic and intrinsic motivation, buffered the declining probability of survey participation over time; however, only if trust in anonymity was comparably low. These results suggest that the beneficial effects of extrinsic and intrinsic motivations on enduring survey participation are especially
prevalent if trust in anonymity is of low to medium size.