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Knowledge Syntheses: A How-To Guide

Overview of systematic review steps and resources to assist researchers conducting reviews

Appraisal and Analysis: Present Only the Best Evidence

Not all studies are trustworthy. In order for your systematic review to represent the best possible evidence, your team must critically appraise each study thoroughly before it is included. The criteria by which you assess included studies should be clearly outlined in your report. You should also maintain a record of which studies have been left out, and the grounds for which they were excluded.

Critical Appraisal Resources

Assessing the Evidence

Extracting Data

Once multiple team members have screened the entire list of references, you will be left with a core group of studies to be included in your review. The next step is to extract the data from each of the studies in order to synthesize their results. The extraction process should be tracked using a standardized data extraction form (see examples below). Data can also be coded for computer analysis. For more information about data extraction, check out this subject guide by the Himmelfarb Health Sciences Library at George Washington University:

Data Extraction Resources

Inclusion/Exclusion: Using Excel

Why use Excel?

Excel is a very common program that is probably already familiar to your research team members. It allows for easy tabulation of large amounts of data - exactly the kind of data that you will use during your systematic review.

How can my team use Excel?

Excel is particularly useful during the inclusion/exclusion phase of your systematic review process because it allows multiple files of the same data to be worked on by different team members at the same time. All studies must be evaluated by each team member separately to avoid bias in your review. After each team member has evaluated all studies, results can also be compared using Excel. These Excel files can be used as supporting documentation in your systematic review, helping to make it transparent and reproducible.

Tutorial: Exporting from RefWorks to Excel

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Books about Critical Appraisal