This research introduces an Output Distance Function (ODF) as a novel method to measure the reduction of undesirable outputs within police forces. Focusing on negative outcomes such as excessive use of force, misconduct, and biased practices, the ODF provides a quantitative tool for assessing the effectiveness of interventions aimed at mitigating these issues. Drawing on data envelopment analysis principles, the ODF allows for a nuanced evaluation of police performance by considering both desirable and undesirable outputs simultaneously. The study explores the application of this metric across diverse law enforcement agencies, offering insights into the impact of various strategies on the reduction of adverse outputs. By providing a structured framework, this research contributes to evidence-based policy decisions and facilitates ongoing efforts to enhance the accountability and efficiency of police forces.