Panel attrition refers to the rate at which participants leave or become unusable within a research panel, whether through voluntary dropout, declining engagement, demographic drift, or fraudulent behavior that triggers disqualification. In research operations, panel attrition is a persistent cost driver: teams running longitudinal studies, brand trackers, or continuous discovery programs must account for participant loss at every wave, or risk drawing conclusions from an increasingly unrepresentative sample. High attrition compounds over time, narrowing the pool of active, qualified participants and inflating recruitment costs per completed interview. Managing panel attrition well requires behavioral screening at intake, incentive structures that sustain genuine engagement, and recruitment pipelines that can replenish losses without compromising sample quality.