Why Plastic Policies Fail in Some Areas but Succeed in Others: A Cluster Analysis of Implementation Patterns in a University Campus

Abstract Implementing single-use plastic (SUP) reduction policies is critical for sustainability but remains a challenge in complex institutions due to heterogeneous compliance. This study evaluated the effectiveness of a restriction policy at the National University of Engineering in Peru, using waste characterization data from 28 ecological points before and after a six-month intervention based on diffusion and non-sanctioning monitoring. The analysis employed Wilcoxon tests for overall impact, K-Means clustering for heterogeneity, and Spearman correlations to assess behavioral patterns. Results revealed no statistically significant overall reduction in plastic bags; however, cluster analysis identified three dis-tinct implementation patterns: 'Successful' (n = 7) with significant reductions, 'Moderate' (n = 13), and 'Critical' (n = 8) where generation increased. Crucially, positive correlations were found between the variation of bags and all other SUPs, indicating a "coherent behavioral response"—integral adoption or rejection of the policy message—rather than a substitution effect. The study concludes that interventions based solely on diffusion without effective governance yield heterogeneous results driven by local context and institutional barriers. Consequently, future policies must combine clear regulations with robust enforcement mechanisms and targeted incentives to ensure full compliance. This approach not only ensures compliance but also prevents resource waste on ineffective strategies, thereby optimizing logistical and operational efforts in the long term.