Knowledge Synthesis and Covidence

After you have run your searches on all the databases you’ve chosen and compiled your search results, you will likely have duplicates of several papers. Deduplication is the process of removing these duplicate articles from your compiled search results.

This can be done within Covidence. A walkthrough of Covidence's deduplication process is linked below:

Zotero can also help you deduplicate your results. More information can be found at:

Once you’ve ensured there’s only one copy of each article in your collection of studies, you can begin the screening process. Since you have downloaded all the results from your searches, there will likely be many articles not relevant to your research question. That’s why the screening process exists: to filter out the irrelevant studies.
Use the inclusion/exclusion criteria you developed to guide your team in selecting articles. Before starting the title/abstract screening process in earnest, pilot the screening process with a small sample of all the articles to be screened. This ensures everyone on your team interprets the inclusion/exclusion criteria consistently and clearly.
 
When your team is ready to begin screening, members will read the titles and abstracts of each article to determine if they meet the inclusion/exclusion criteria. 

• If at least two members of your team independently conclude that an article should be included, it moves to the next round. 
• If two team members choose to exclude it, the article is discarded. 
• In case of a disagreement, a third team member will break the tie.

The next step is full-text screening. Two team members review the full text of the remaining articles to ensure that the papers are still relevant and independently determine whether to include or exclude them based on the established criteria.  They will look for relevant outcomes reported. If an article is to be excluded, the reasons must be explicitly noted.
 
All screening steps can be facilitated by Covidence. To learn more, you can access Covidence's in-depth walkthrough at the link below:

After identifying all the relevant studies for your review, the next step is to appraise the quality of the methods used in each study. This helps determine the risk of bias in their design, execution, and analysis. While this step is not mandatory for all reviews, it is recommended. For systematic reviews, it is required. 
Assessing bias in the studies used in your review ensures the credibility and quality of your review. (Cochrane, 2024)
 

Appraisal Tools

There are several tools available to standardize your team's approach to assessing studies for validity and risk of bias. These tools are organized according to  the type of study being appraised:

Repositories of Tools for Various Study Types

Tools for Non-Randomized Studies or Observational Studies

Tools for Reviews

Tools for Grey Literature