Measuring drug policy evolution: A cross-country analysis.

Drug policies significantly impact public health and criminal justice outcomes, yet quantitative tools for systematically comparing approaches across jurisdictions remain limited. This paper uses a state-of-the-art comparative law method - leximetrics - to construct the Illicit Drugs Policy Indexes (IDPI), a valuable resource for assessing the evolution of drug policies over time within a specific country as well as across countries. The IDPI consists of a set of indexes corresponding to multiple dimensions of drug policy, including laws around consumption, possession and traffic. These indexes examine illicit drug laws and policies across seven countries: Australia, Canada, France, Italy, Netherlands, Portugal and the United Kingdom, over a timeframe of twenty years from 1996 to 2016. Our results identify significant turning points in the evolution of laws regarding drugs, often indicating a shift towards less criminal-oriented approaches. Moreover, the paper identifies the countries which progressed more in that direction, over time. The underlying IDPI methodology provides policymakers and researchers with a standardized framework for evidence-based drug policy evaluation and reform, adaptable across jurisdictions.