Original Article| Volume 79, P120-129, November 2016

Evidence & Gap Maps: A tool for promoting evidence informed policy and strategic research agendas


      A range of organizations are engaged in the production of evidence on the effects of health, social, and economic development programs on human welfare outcomes. However, evidence is often scattered around different databases, web sites, and the gray literature and is often presented in inaccessible formats. Lack of overview of the evidence in a specific field can be a barrier to the use of existing research and prevent efficient use of limited resources for new research. Evidence & Gap Maps (EGMs) aim to address these issues and complement existing synthesis and mapping approaches. EGMs are a new addition to the tools available to support evidence-informed policymaking. To provide an accessible resource for researchers, commissioners, and decision makers, EGMs provide thematic collections of evidence structured around a framework which schematically represents the types of interventions and outcomes of relevance to a particular sector. By mapping the existing evidence using this framework, EGMs provide a visual overview of what we know and do not know about the effects of different programs. They make existing evidence available, and by providing links to user-friendly summaries of relevant studies, EGMs can facilitate the use of existing evidence for decision making. They identify key “gaps” where little or no evidence from impact evaluations and systematic reviews is available and can be a valuable resource to inform a strategic approach to building the evidence base in a particular sector. The article will introduce readers to the concept and methods of EGMs and present a demonstration of the EGM tool using existing examples.


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        • White H.
        • Waddington H.
        Why do we care about evidence synthesis? An introduction to the special issue.
        J Dev Effect. 2012; 4: 359-387
        • Ioannidis J.P.
        Evolution and translation of research findings: from bench to where?.
        PLoS Clin Trials. 2006; 1: e36
        • Moher D.
        • Stewart L.
        • Shekelle P.
        All in the family: systematic reviews, rapid reviews, scoping reviews, realist reviews, and more.
        Syst Rev. 2015; 4: 183
        • Waddington H.
        • et al.
        3ie Evidence Gap Map.
        International Initiative for Impact Evaluation, London2015 (Available at) (Accessed July 28, 2016)
        • The SURE Collaboration
        SURE checklist for making judgements about how much confidence to place in a systematic review.
        in: SURE guides for preparing and using policy briefs. Version 2.1. 2011 (updated November 2011. Sure Collaboration, Available at Accessed September 28, 2016)
        • Greenhalgh T.
        • Howick J.
        • Maskrey N.
        Evidence based medicine: a movement in crisis?.
        BMJ. 2014; 348: 3725
        • Lum C.
        • Koper C.S.
        • Telep C.W.
        The evidence-based policing matrix.
        J Exp Criminology. 2011; 7: 3-26
        • McCandless D.
        Information is Beautiful.
        Collins, London2009
        • Rosling H.
        • Zhang Z.
        Health advocacy with Gapminder animated statistics.
        J Epidemiol Glob Health. 2011; 1: 11-14
        • Schlossera R.W.
        • Wendt O.
        • Sigafoos J.
        Not all systematic reviews are created equal: considerations for appraisal.
        Evid Based Commun Assess Interv. 2007; 1: 138-150
        • Vojtkova M.
        • Stevenson J.
        • Verboom B.
        • Prasannakumar Y.
        • Snilstveit B.
        Productive Safety Nets Evidence Gap Map, 3ie Evidence Gap Map.
        International Initiative for Impact Evaluation, London2014 (Available at) (Accessed July 28, 2016)
        • Snilstveit B.
        • Stevenson J.
        • Philips D.
        • Gallagher E.
        Primary and Secondary Education Evidence Gap Map, 3ie Evidence Gap Map.
        International Initiative for Impact Evaluation, London2015 (Available at) (Accessed July 28, 2016)
        • Baird S.
        • Ferreira F.H.G.
        • Özler B.
        • Woolcock M.
        Relative effectiveness of conditional and unconditional cash transfers for schooling outcomes in developing countries: a systematic review.
        Campbell Syst Rev. 2013; 8
        • Taylor-Robinson D.C.
        • Maayan N.
        • Soares-Weiser K.
        • Donegan S.
        • Garner P.
        Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin, and school performance.
        Cochrane Database Syst Rev. 2015; : 1-157
        • Tanner J.
        • et al.
        Delivering the millennium development goals to reduce maternal and child mortality: a systematic review of impact evaluation evidence.
        Independent Evaluation Group (IEG), World Bank, Washington D.C2013
        • Lavis J.N.
        How can we support the use of Systematic Reviews in policymaking?.
        PLoS Med. 2009; 6: e1000141
        • Parkhill A.F.
        • Clavisi O.
        • Pattuwage L.
        • Chau M.
        • Turner T.
        • Bragge P.
        • et al.
        Searches for evidence mapping: effective, shorter, cheaper.
        J Med Libr Assoc. 2011; 99: 157-160
        • Khangura S.
        • Konnyu K.
        • Cushman R.
        • Grimshaw J.
        • Moher D.
        Evidence summaries: the evolution of a rapid review approach.
        Syst Rev. 2012; 1: 1-9
        • The UK Civil Service
        Government Social Research REA Toolkit 2008 [online].
        2008 (Available at) (Accessed July 17, 2013)
        • Bragge P.
        • Clavisi O.
        • Turner T.
        • Tavender E.
        • Collie A.
        • Gruen R.
        The Global Evidence Mapping Initiative: scoping research in broad topic areas.
        BMC Med Res Methodol. 2011; 11: 92
        • Greenhalgh T.
        • Peacock R.
        Effectiveness and efficiency of search methods in systematic reviews of complex evidence: audit of primary sources.
        BMJ. 2005; 331: 1064-1065
        • O'Mara-Eves A.
        • Thomas J.
        • McNaught J.
        • Miwa M.
        • Ananiadou S.
        Using text mining for study identification in systematic reviews: a systematic review of current approaches.
        Syst Rev. 2015; 4: 59
        • Shemilt I.
        • Simon A.
        • Hollands G.J.
        • Marteau T.M.
        • Ogilvie D.
        • O'Mara-Eves A.
        • et al.
        Pinpointing needles in giant haystacks: use of text mining to reduce impractical screening workload in extremely large scoping reviews.
        Res Synth Methods. 2015; 5: 31-49
        • Thomas J.
        Diffusion of innovation in systematic review methodology: why is study selection not yet assisted by automation?.
        OA Evid Based Med. 2013; 1: 1-6
        • Schünemann H.J.
        • Oxman A.D.
        • Higgins J.P.T.
        • Vist G.E.
        • Glasziou P.
        • Guyatt G.H.
        Chapter 11.
        (updated March 2011)in: Higgins J.P.T. Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. The Cochrane Collaboration, 2011 (Available at) (Accessed July 28, 2016)
        • Becker L.A.
        • Oxman A.D.
        ‘Overviews of reviews’, Chapter 22.
        (updated March 2011)in: Higgins J.P.T. Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. The Cochrane Collaboration, 2011 (Available at) (Accessed July 28, 2016)
        • Anderson S.
        • Allen P.
        • Peckham S.
        • Goodwin N.
        Asking the right questions: scoping studies in the commissioning of research on the organisation and delivery of health services.
        Health Res Policy Syst. 2008; 6: 1-12
        • Cooper H.
        • Hedges L.V.
        • Valentine J.C.
        The handbook of research synthesis and meta-analysis.
        Russell Sage Foundation, New York2009
        • Ganann R.
        • Ciliska D.
        • Thomas H.
        Expediting systematic reviews: methods and implications of rapid reviews.
        Implement Sci. 2010; 5: 1-10
        • Gaarder M.
        Evidence on links in the causal chain: agriculture, nutrition and health.
        International Initiative for Impact Evaluation, Delhi2010
        • Arksey H.
        • O'Malley L.
        Scoping studies: towards a methodological framework.
        Int J Soc Res Methodol. 2005; 8: 19-32
        • Davis K.
        • Drey N.
        • Gould D.
        What are scoping studies? A review of the nursing literature.
        Int J Nurs Stud. 2009; 46: 1386-1400
        • Grant M.J.
        • Booth A.
        A typology of reviews: an analysis of 14 review types and associated methodologies.
        Health Info Libr J. 2009; 26: 91-108
        • Levac D.
        • Colquhoun H.
        • O'Brien K.K.
        Scoping studies: advancing the methodology.
        Implementation Sci. 2010; 5: 1-9
        • Bates S.
        • Clapton J.
        • Coren E.
        Systematic maps to support evidence base in social care.
        Evid Policy. 2007; 3: 539-551
        • Bates S.
        • Rutter D.
        Developing the process of systematic mapping-the social welfare literature.
        SCIE, London, 2008 (Available at) (Accessed July 28, 2016)
        • Oakley A.
        • Gough D.
        • Oliver S.
        • James T.
        The politics of evidence and methodology: lessons from the EPPI-Centre.
        Evid Policy. 2005; 1: 5-31
        • Chandler J.
        • Churchill R.
        • Higgins J.
        • Lasserson T.
        • Tovey D.
        Methodological Expectations of Cochrane Intervention Reviews (MECIR): Methodological standards for the conduct of new Cochrane Intervention Reviews, Version 2.2.
        2011 (Available at) (Accessed July 17, 2013)
      1. Higgins J.P.T. Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. The Cochrane Collaboration, 2011 (updated March 2011. Available at) (Accessed July 28, 2016)
        • Gough D.
        • Thomas J.
        ‘Commonality and diversity in reviews’, Chapter 3.
        in: Gough D. Oliver S. Thomas J. An introduction to Systematic Reviews. Sage, London2012