Errors in the Pursuit of Justice: An Experimental Study of Type I and Type II Trade-offs

This paper investigates how individuals make trade-offs between two types of judicial error: Type I errors (wrongful convictions) and Type II errors (wrongful acquittals). We introduce a novel experimental framework that isolates participants’ preferences in the absence of legal guidance or institutional framing. In a stylized justice task, participants are given limited resources to allocate toward reducing each type of error, allowing us to observe how they prioritize fairness and punishment under constraint. Study I compares behavior in hypothetical versus consequential settings, while Study II expands the design to explore additional factors, including individual versus population-level framing and the inclusion of past behavior information. We also manipulate both the size of the endowment and the effectiveness of each resource unit, simulating real-world policy trade-offs. Across all treatments, participants consistently prioritize reducing Type I errors, without the “beyond a reasonable doubt” standard. Resource effectiveness significantly influences allocation behavior, and we observe systematic demographic differences: men allocate more resources to reducing Type I errors than women. These findings shed light on how individuals approach moral trade-offs in legal contexts and offer implications for institutional design and public support for criminal justice policies.