cooperation fee; compensation; reimbursement
A payment made to someone for their participation or cooperation, such as in a clinical trial, survey, or study. Often used in formal or institutional contexts.
If you participate in a clinical trial, a gratuity will be paid as a cooperation fee.
Those who complete the survey will receive a book card as compensation for their cooperation.
Compound of 協力 (cooperation) and 費 (expense, cost). The term is a modern coinage used in administrative and research contexts.