The impact of sample retention and further analysis on doping behavior and detection: evidence from agent-based simulations.

Introduction: Despite extensive testing efforts in anti-doping work, a persistent gap remains between low doping detection rates and substantially higher estimated doping prevalence in sports. Sample Retention and Further Analysis (SFA), which allows samples to be stored for up to ten years for future testing, offers a potential strategy to close this gap by increasing both detection and deterrence of doping. Methods: This study employs an agent-based modeling approach to simulate interactions among key stakeholders: athletes, anti-doping organizations, laboratories, and event organizers. The model captures athlete decision-making regarding doping, influenced by perceived sanction certainty and swiftness. SFA parameters, such as number of stored samples and duration of storage, were systematically varied to assess their impact. Results: Simulations show that increasing both the quantity of stored/retested samples and the storage duration reduces doping prevalence. A combined approach yields the strongest effect, with higher detection rates and lower doping behavior. However, regression analysis reveals diminishing returns at higher implementation levels, suggesting a non-linear effect. Discussion: The findings provide quantitative evidence that SFA enhances not only detection capacity but also deterrence by increasing the perceived long-term risk of sanctions. Effective SFA implementation requires strategic calibration to optimize impact. These results underscore the potential of SFA as a key component in anti-doping strategies and call for empirical validation and integration of additional behavioral factors in future research.