Improving Conduct and Reporting of Narrative Synthesis of Quantitative Data (ICONS-Quant)

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In systematic reviews where meta-analysis of quantitative data is inappropriate due to heterogeneity in outcomes, study design, etc., the alternative approach is often to synthesise the data narratively. Narrative synthesis involves collating study findings into a coherent textual narrative, with descriptions of differences in context, validity and other study characteristics. As in meta-analysis, narrative synthesis seeks to draw conclusions that reflect the quality of included evidence, and comparisons across studies are used to explain heterogeneity.

Narrative synthesis is criticised as it can lack transparency. An assessment of systematic reviews of public health interventions found that while narrative synthesis is often used to synthesise studies, narrative synthesis methods are rarely reported (read the published results from this work here). This lack of transparency introduces bias into the synthesis. This raises questions about the validity and utility of reviews using narrative synthesis. To date, there has been limited work to support improved conduct and transparent reporting in narrative synthesis.

ICONS-Quant intends to provide clear reporting guidelines for narrative synthesis of quantitative data in systematic reviews. This will be based on key sources on narrative synthesis, including guidance by the UK’s Economics & Social Science Research Council (ESRC). The ESRC guidance emphasises the importance of transparency when moving between the data and review conclusions, by using graphical, or structured tabulation of the data, as well as manipulation of statistical data.

The ICONS-Quant project consists of four Work Programmes (WPs) to develop a reporting guideline for narrative synthesis and supporting materials for existing guidance. In line with recommendations for best practice in developing reporting guidelines, we will:

  • WP 1: identify the need for the ICONS-Quant guideline
  • WP 2: conduct a Delphi survey and consensus meeting
  • WP 3: enhance existing guidance on narrative synthesis
  • WP 4: develop learning materials for implementation of narrative synthesis.

Details of the ICONS-Quant project have been registered with the Enhancing the quality and Transparency of Health Research (EQUATOR) Network, which provides a database of reporting guidelines in development.

The protocol for the ICONS-Quant project can be read here.

This work has been presented in training workshops at the Annual International Cochrane Colloquia and by invitation locally, and by webinar.


Amanda Sowden, University of York
Joanne McKenzie, Monash University  

Project advisory group

Simon Ellis (National Institute for Health and care Excellence, NICE)
Jamie Hartmann-Boyce (Cochrane Tobacco Addiction Group)
Vivian Welch (Campbell Collaboration)
Rebecca Ryan (Cochrane Consumers and Communication Group)
Sasha Shepperd (Cochrane Effective Practice and Organisation of Care Group)
James Thomas (Evidence for Policy and Practice Information and Co-ordinating (EPPI) Centre)

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