This report presents the findings of the sixth edition of CHI’s Effectiveness Map. This Evidence and Gap Map (EGM) presents the existing evidence and gaps in the literature on the effectiveness of various interventions being used to improve the lives and welfare of people experiencing or at risk of homelessness in high-income countries. The 800 records in the current edition of the updated map make this EGM one of the largest open access resources for locating studies with the effectiveness of interventions for improving lives and welfare of people experiencing or at risk of homelessness. The EGM is a useful resource for stakeholders and policymakers to make evidence-informed decisions and investment of resources for improving the lives and welfare of people experiencing or at risk of homelessness.

This EGM plots studies of eligible interventions for people experiencing or at risk of homelessness for the selected outcomes with study designs aimed at assessing the effectiveness of interventions. The EGM is an interactive intervention-outcome matrix. Through this framework, the available evidence is categorised based on the interventions and outcomes used in the studies. The interventions focus on different aspects, such as health, legislation, prevention, and employment. The outcome measures include health, housing stability, education and employment, and crime and justice. As this is an effectiveness map, the studies included here are either impact evaluations (IEs) or systematic reviews (SRs) of IEs. Users can explore evidence for specific countries, target populations, study designs, or others, using the various filters.

The new editions of the map also draw attention to the relevance of regular annual updates. The first edition of this map, published in 2018, had 221 studies. Over the years there has been significant growth in the number of effectiveness studies and systematic reviews of impact evaluations demonstrating ‘what works’ for people experiencing or at risk of homelessness. There has been a noticeable increase in the number of SRs compared to the previous edition. The proportion of SRs among newly included studies increased from 8% in the 2022 update to 30%. 

As with most other fields of knowledge, the evidence on homelessness in the EGM is concentrated around certain interventions. Studies of health and social care interventions are the most studied interventions for homelessness, with 356 studies (approximately 45% of all studies in the EGM). Studies about services and outreach interventions and interventions providing accommodation and accommodation-based services account for 338 (42%) and 283 (35%) studies respectively. On the other hand, interventions about communications, legislation, and financing account for only 13%, 134% and 15% studies of the map respectively.