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Evidence and Gap Maps

See the big picture of evidence on homelessness interventions – what do we know, and what don’t we know?

ABOUT THE Evidence & Gap Maps

Our Evidence and Gap Maps bring together evidence on homelessness interventions from around the world to highlight where evidence does or doesn’t exist on what works and why they work or not. This helps target research investments faster and in a more strategic, impactful way.

The Effectiveness Map, or ‘what works’ map - captures impact evaluations and effectiveness reviews. The Implementation Issues or ‘why things work or not’ map focuses on the factors that impact on the successful implementation of homelessness interventions. Together the two maps capture around 500 studies on interventions – the largest resource of its type anywhere in the world.

These EGMs have been created with our partners at The Campbell Collaboration and Heriot-Watt University. Both will be updated at regular intervals. The Effectiveness map has now been categorised to show how much confidence we can have in the findings: high, medium and low confidence.

The Effectiveness Map

Also known as the ‘what works’ map. Explore it to find 260 quantitative impact evaluations and effectiveness reviews of homelessness interventions. It has now been categorised to show how much confidence we can have in the findings: high, medium and low confidence. View the report behind this map as well as the Standards of Evidence, and critical appraisal.

Version 1.0.5   Last updated 22/08/2019

The Implementation Issues Map

Also known as the ‘why things work or not’ map. Use it to find 246 qualitative process evaluations that examined factors which help or hinder the successful implementation of homelessness interventions. At the moment the information is displayed in two digital tools – one on barriers and another on facilitators – but an integrated version will be available in future. View the report behind this map here.

Version 1.0.4   Last updated 16/07/2019

Update 5.5.18: EPPI reviewer team are experiencing some issues with the map loading in Internet Explorer. Please try using a different browser while they look into this issue (no problems currently reported in Chrome or Firefox). Please note our maps are not yet mobile friendly.

Learn more

Read more about the maps and what they tell us on our blog. Here's a post announcing our first map on the blog and a write up about part 2 of our maps on the blog here.


Do remember to share any studies we missed at