<br />1.1 This report is based on an international Rapid Evidence Assessment (REA) covering service evaluations and research on services for homeless and potentially homeless people with a history of substance misuse. The review was commissioned by the Scottish Government to examine the range of services that are available in comparable countries and to look at how service effectiveness is measured, following a recommendation from the Homelessness and Substance Misuse Advisory Group (HSMAG). The main aim of the research was that it would make suggestions about which services from other countries might be suitable for Scotland and on how best, drawing on international experience, to measure the effectiveness and efficiency of these services. 1.2 The three main objectives of the REA review were as follows: • To identify and review available evidence on service models and approaches that produce positive outcomes for people with substance misuse problems who are either homeless or at risk of homelessness. • Outline and assess how positive outcomes in effective services are recognised and measured. • Develop potential outcome measures for services.