Evidence portals

Evidence portals and evidence databases

Evidence portals are websites which present research evidence in a form accessible to policy makers and practitioners. A good portal is easy to navigate, with clearly defined interventions, presenting the best available evidence on the most cost effective approaches to achieving the desired outcomes. The portal should provide links to the underlying research.

An evidence portal is different to an evidence database. An evidence database provides links to rigorous reviews and primary studies, often allowing searching by sector and country. In an evidence portal this evidence has been further translated by the portal manager to make it more accessible.

Evidence portals are aimed at consumers of evidence. Evidence databases may be used by consumers, but are also useful for producers of evidence synthesis as part of their search.

There are many evidence portals for different subjects. Here we feature some of the main ones based on systematic review evidence or primary studies.

Evidence portals
Crime and Justice 
Evidence-based policing matrix (Center for Evidence-Based Crime Policy, George Mason University, USA) Policing interventions classified in four dimensions (focused, scope, proactivity and effectiveness).
Best practice in drug interventions (EMCDDA, EU) Evidence on interventions to reduce substance abuse and support drug users.
From the National Institute of Justice's Office of Justice Programs, USA:
Crime Solutions website has Reviewers Profiles of programs and practices with research findings, and
Model Programs Guide (MPG) contains information about evidence-based juvenile justice and youth prevention, intervention, and reentry programs.

Early years toolkit (Education Endowment Foundation, UK) Evidence of the effectiveness of early years’ interventions showing cost, strength of evidence and impact.
Teaching and Learning Toolkit (Education Endowment Foundation, UK) Evidence of approaches to improving learning outcomes showing cost, strength of evidence and impact.
What Works Clearing House (Institute of Education Sciences, USA)
The Education Elf Blogs on the effectiveness of education interventions based on primary studies and systematic reviews.


Environment and Conservation
Evidence for Nature and People Data portal features data from a systematic map on the impacts of conservation on human well-being in non-OECD nations, designed to help users explore the existing evidence on linkages between nature and people.
Conservation Evidence is a free, authoritative information resource with evidence from the scientific literature about the effects of conservation interventions, such as methods of habitat or species management.


Mental Elf Blogs on mental elf issues based on primary studies and systematic reviews.
The Lifestyle Elf Blogs on lifestyle issues based on primary studies and systematic reviews.
Optimal Ageing Reviews of evidence on ageing related evidence.

Social welfare
Child Welfare Clearing House (California Evidence-Based Clearing House, USA) Portals for programmes related to child welfare. Programmes are also included for which there is no evidence of effectiveness.
The Child Elf Blogs on the effectiveness of interventions for child wellbeing based on primary studies and systematic reviews.

Evidence databases

This list is restricted to databases ofeffectiveness studies and systematic reviews. We do not include in this listgeneral sector databases, such as Medline, Econlit and ERIC. A list of theseresources is provided at Links.

The Campbell Library Systematic reviews of social and economic policies published by the Campbell Collaboration.
EPPI-Centre Knowledge Library Systematic reviews conducted and supported by the EPPI-Centre on a broad range of topics.

Environment and Conservation
Environmental Evidence Library Systematic reviews of environmental issues published by the Collaboration for Environmental Evidence

Epistemonikos Database of primary studies and systematic reviews in health.
Cochrane Library Systematic reviews on health published by Cochrane.
Joanna Briggs Institute Library Systematic reviews published by the Joanna Briggs Institute

International development
International Initiative for Impact Evaluation (3ie) Database of primary studies and systematic reviews in international development.
Evidence aid Systematic reviews of relevance to natural disasters, humanitarian crises or major healthcare emergencies, that include health outcomes. Organized alphabetically by topic.


Clearinghouse for Labor Evaluation and Research (CLEAR, US Department of Labor) The clearinghouse identifies and summarizes many types of research on labor topics, including descriptive statistical studies and outcome analyses, implementation, and causal impact studies.

If you want to recommend an evidence portal to us to include on this webpage, please email info@campbellcollaboration.org