The promise of a reward, be it financial compensation or e-gifts, can motivate group members to not only participate but also stay throughout the duration of the clinical study and give better responses.
Rewards create a sense of responsibility and dedication to fulfill their role in the study. This increased motivation and commitment increases the likelihood of participants to adhere to the study procedures.
Rewards establish trust and goodwill between researchers and participants. When participants receive the promised rewards promptly and fairly, it builds a positive foundation for the relationship.