Assessing options for cannabis law reform: A Multi-Criteria Decision Analysis (MCDA) with stakeholders in New Zealand

A number of jurisdictions are considering or implementing different options for cannabis law reform, including New Zealand. Multi-Criteria Decision Analysis (MCDA) helps facilitate the resolution of complex policy decisions by breaking them down into key criteria and drawing on the combined knowledge of experts from various backgrounds.

To rank cannabis law reform options by facilitating expert stakeholders to express preferences for projected reform outcomes using MCDA.

A group of cannabis policy experts projected the outcomes of eight cannabis policy options (i.e., prohibition, decriminalization, social clubs, government monopoly, not-for-profit trusts, strict regulation, light regulation, and unrestricted market) based on five criteria (i.e., health and social harm, illegal market size, arrests, tax income, treatment services). A facilitated workshop of 42 key national stakeholders expressed preferences for different reform outcomes and doing so generated relative weights for each criterion and level. The resulting weights were then used to rank the eight policy options.

The relative weighting of the criteria were: "reducing health and social harm" (46%), "reducing arrests" (31%), "reducing the illegal market" (13%), "expanding treatment" (8%) and "earning tax" (2%). The top ranked reform options were: "government monopoly" (81%), "not-for-profit" (73%) and "strict market regulation" (65%). These three received higher scores due to their projected lower impact on health and social harm, medium reduction in arrests, and medium reduction in the illegal market. The "lightly regulated market" option scored lower largely due its projected greater increase in health and social harm. "Prohibition" ranked lowest due to its lack of impact on reducing the number of arrests or size of the illegal market.

Strictly regulated legal market options were ranked higher than both the current prohibition, and alternatively, more lightly regulated legal market options, as they were projected to minimize health and social harms while substantially reducing arrests and the illegal market.