How to assess the evidence when a statistical synthesis is not possible

Workshop category: 

  • Translation (linguistic translation of Cochrane content)
Date and Location


Tuesday 18 September 2018 - 11:00 to 12:30


Contact persons and facilitators

Contact person:


Santesso N1, Thomson H2, Brennan S3
1 Cochrane Canada, GRADEing Methods Group, McMaster University, Canada
2 Cochrane Public Health, University of Glasgow, United Kingdom
3 Cochrane Australia, Australia


Schunemann H1, Mustafa R2
1 GRADEing Methods Group, McMaster University, Canada
2 University of Kansas Medical Center, USA
Target audience

Target audience: 

review authors, editors, guideline developers

Level of difficulty: 

Type of workshop

Type of workshop : 



In over 20% of Cochrane Reviews, it is not possible to conduct a meta-analysis, and instead the quantitative data are synthesised narratively. After synthesising the evidence, it is also helpful to readers and users of systematic reviews if that evidence is assessed and presented clearly. When there is a meta-analysis, authors use GRADE to assess the certainty and present the information in 'Summary of findings' tables. GRADE can also be used when a statistical synthesis is not possible. The 'Summary of findings' table, and the software GRADEpro used to create the 'Summary of findings' table, can also include outcomes with narrative syntheses.

1) Provide guidance about how to apply the GRADE domains where there is no statistical estimate of effect
2) Provide guidance on the production of 'Summary of findings' tables for outcomes that have been synthesized narratively
3) Give participants an opportunity to practice applying the guidance to examples
4) Obtain feedback from participants about the current guidance and challenges

We will briefly describe the GRADE domains to assess the certainty of evidence for an outcome and how the domains are used when evidence is synthesised narratively. We will explain risk of bias, imprecision, indirectness, inconsistency, publication bias, and other GRADE domains. Participants will spend most of the workshop applying the concepts in small groups.

Relevance to patients and consumers: 

The target audience of this workshop is systematic review authors. The relevance to patients and consumers reflects the purpose of GRADE and is to improve access to, interpretation and use of evidence synthesis through improved consistency and transparency of evidence statements from evidence synthesis. Specifically the workshop focusses on how to apply the GRADE assessments and prepare 'Summary of findngs' tables to reviews using non-statistical methods, this applies to over 20% of Cochrane Reviews. As such we aim to facilitate improved access and use of reviews which incorporate diverse sources of evidence.