We will also conduct a Return on Investment (ROI) analysis which will seek to monetarize the costs of decriminalization and its potential benefits, both expressed in monetary terms. The ROI will quantify all costs of decriminalization and put it into relation with potential savings, for example, resulting from reductions in arrests and convictions for possession of illicit substances. All costs and benefits will be assessed from a societal perspective and the timeframe will be four years. Costs will be derived in line with current practices for cost studies on drug use and will rely on all of the other data collected (including from the qualitative interviews and quantitative analyses) and determinations of which factors could be causally linked to decriminalization.