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Liaison & Diversion schemes are cost effective
RAND evaluation of the impact of the national model of Liaison and Diversion schemes in police custody.

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Outcome evaluation

The RAND Corporation has just published its Outcome evaluation of the national model for liaison and diversion. Liaison and Diversion (L&D) services are designed to support people with mental health problems, a learning disability, substance misuse problems and other vulnerabilities including unstable accommodation and risk of self-harm or domestic abuse. The main activities of L&D are identification, screening, assessment and referral to other services.

The research was commissioned to answer two key questions:

  1. What impact, if any, did the implementation of the National Model of Liaison and Diversion have on health service utilisation; reconviction; diversion from the criminal justice system; or timeliness of court processes?
  2. What were the economic effects of any identified impacts?

The research

Liaison and Diversion (L&D) services identify and support people in the criminal justice system who have vulnerabilities such as mental and physical health issues and learning disabilities.

RAND’s evaluation of the National Model for L&D was conducted at 27 sites in England using a novel, linked data set combining national level administrative data from both the healthcare and criminal justice sectors. The data set combined information from four separate healthcare sources (Hospital Episode Statistics Accident & Emergency, Mental Health Services Datasets, Improving Access to Psychological Therapies database, National Drug Treatment Monitoring System) and two separate criminal justice sources (Police National Computer, Her Majesty’s Courts and Tribunals
Service). However, the National Model was implemented before the evaluation was commissioned, making it impossible to directly gather long-term baseline data from sites before the intervention was deployed.

This evaluation examined the impact of the National Model for L&D on health service utilisation, reconviction, diversion from the criminal justice system and timeliness of court processes, as well as the economic effects of identified impacts. Outcomes included:

  • Accident & Emergency attendances
  • Referrals and attendances at specialist mental health services
  • Referrals and attendances at Improving Access to Psychological Therapies services
  • Referrals and attendances at drug and alcohol treatment services, and data on quality of life and other wellbeing measures
  • Offending, including offence type and outcome
  • Court processes, including duration and number of hearings.

Analyses conducted across the data sources consistently showed that L&D services are successfully engaging with a group of service users with a broad range of vulnerabilities, often at a time of acute crisis when they are most in need of support. The strongest effect appeared to be an increase in diversion from custodial sentences, although L&D services may also increase referrals to mental health and drug and alcohol treatment services.

There was no evidence of an impact on offending, but also no evidence that outcomes became worse due to L&D referral.

Key findings

The main findings from the research were:

  • L&D services succeeded in engaging people with a broad range of vulnerabilities.
  • L&D services appear to intervene at a point of crisis.
  • L&D services appear to increase diversion from custodial sentences.
  • The interventions offered, and their uptake, varies by individual and by L&D site, and range from advice and brief interventions, to primary care referral, to detention for psychiatric assessment.
  • Following L&D referral, there is a short-term increase in referral to mental health services.
  • Drug and alcohol treatment referral and attendance may increase following L&D referral.
  • Referral to L&D services does not appear to reduce offending.
  • Court processes are not significantly affected by L&D services.
  • The L&D programme contributes to savings in the criminal justice system between £13.1 million and £41.5 million through diversion from custody and consequent increases in productivity.


  • L&D services could be improved through increased capacity for onward referrals.
  • Approaches could be added to support people who have multiple vulnerabilities but who are not currently eligible for onwards referral because no single vulnerability meets the required therapeutic threshold.

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