Background: Police-led drug diversion (PDD) provides alternatives to prosecution and punishment of people who are found in possession of illicit drugs. It involves requiring people to participate in a therapeutic or educative intervention instead of receiving a criminal sanction and record. Some small-scale studies have suggested this can be effective (and cost-effective) in reducing the harms of criminalisation and improving outcomes for people who use drugs. However, it is also possible that PDD is ineffective at scale (with possible net-widening effects), and inequitable, e.g. for people who are racialised as Black.

Aim: This realist evaluation aimed to explore the effects, mechanisms, moderators, implementation and economy of PDD in England and Wales. This evaluation was funded by the UK Cabinet Office to inform UK government spending decisions.

Methods: The research was collaboratively designed, implemented and analysed, including with people with direct experience of being policed. We carried out a mixed methods evaluation of the process, outcomes, equity and cost consequences of PDD schemes. Starting from a provisional programme theory developed through realist review, we linked quantitative data from over 40,000 suspects (from 15 police forces) with administrative data on these people’s drug treatment entry and police-recorded offending. We also collected qualitative data from over 220 participants in interviews and focus groups with police officers, PDD practitioners, and diverted suspects in three focus police force areas. We analysed these data, using the EMMIE framework, to identify important configurations of contexts, mechanisms and outcomes that explain the effects, costs and equity of PDD.

Results: Analysis is ongoing, and will be more complete by the time of the conference. Our qualitative analysis focuses on processes of police discretion, inter- and intra-agency partnerships, the motivations of people who use drugs to engage with PDD, how their needs are assessed, and how the contexts and mechanisms of PDD affects service user experiences. Quantitative analysis will show whether people in areas with PDD schemes are more likely to enter drug treatment, and less likely to re-offend. Economic analysis will show whether PDD schemes are cost-effective, and on which agencies the costs and benefits fall. Equity analysis so far suggests that the introduction of PDD schemes is followed by reductions in criminalisation, but with continuing disparities between ethnic groups.