Library: Systematic reviews: Assess the evidence

Assessing the quality of evidence

Having identified the studies to include in your review, you need to collate the data you have found in a meaningful way. This will require some knowledge of statistical analysis techniques.

Guide to using Covidence
The University subscribes to the tool, Covidence, which you can use to screen references, review the full text of documents, assess risks of bias, extract both study characteristics and outcomes, and export references and data. To find out how to access and use Covidence, refer to the above guide.

Cochrane Interactive Learning resources

Modules 6-7 of Cochrane Interactive Learning have information on performing a statistical analysis. The Library is subscribing to Cochrane Interactive Learning.

Log in to Module 6: Cochrane Interactive Learning

How to analyse different types of data, effect measures, undertaking meta-analysis, recognising heterogeneity.

Log in to Module 7: Cochrane Interactive Learning

How to interpret results of systematic analysis, using GRADE method to report uncertainty of evidence.

GRADE

GRADE
A tool for grading quality of evidence in healthcare publications and guidelines. Developed by the Grading of Recommendations Assessment, Development and Evaluation Working Group.

Calculating effect size

Effect Size Calculator
Calculates effect sizes for meta-analysis (taking into account risk-ratios correlation coefficients and other factors). Provided by Campbell Collaboration.

Assessing bias

Catalogue of bias
Advice on recognising and avoiding different types of bias that effect health evidence. Invites input from researchers. Provided by CEBM (University of Oxford).
Critically appraising for antiracism
Tips on checking for potential biases (including confirmation biases falsely identifying causal relationships). Presented by Ramona Naicker (Northern Care Alliance).
Guide to using Covidence
You can use the Covidence tool to add comments and highlighting to PDFs where you identify any potential bias. Your actions are automatically recorded in your 'risk of bias' tables. To find out how to access and use Covidence, refer to the above guide.

Get help with statistics

Mathematics Resources Centre (MASH)
MASH helps all students at the University with mathematics and statistics problems.

Library resources on statistics

O'Reilly Learning This link opens in a new window

A database of e-books that you can search. For example, enter the term 'statistics' or 'Excel' or the name of a statistical package such as 'SPSS'.