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Systematic Reviews

This is a guide for learning about systematic reviews.

Screening Articles

Once you have completed literature searching and compiled all citations, it is time to screen the results. The purpose of screening is to eliminate studies that do not meet your inclusion criteria. Two independent reviewers should screen all studies, starting with a title and abstract screening, followed by a full-text screening. A third reviewer or the review team should resolve any conflicts.

All voting should be blinded, meaning team members should be unable to see how others cast their votes.


At the title/abstract screening stage, reviewers should read the title and abstract before making a decision. 

  • No: This reference does not meet inclusion criteria and should not be included in the systematic review.
  • Maybe: There is not enough information in the title/abstract to make a decision (move to full-text screening stage).
  • Yes: This reference appears to meet inclusion criteria and should move to the full-text screening stage.

After you complete title/abstract screening, you will need to review any conflicts between reviewers and resolve if references should move forward to full text screening or be marked as irrelevant.

There are several tools listed below in the Other Tools" box that can aid in the screening and coding process, including Covidence, Rayyan, and DistillerSR.

Citation Managers

Which citation managers work best for systematic reviews?

When choosing a citation manager for a systematic review, in addition to factors like cost, format, and storage capacity, you will also need to consider how it will perform on systematic review tasks.

The library supports:

  • EndNote is robust and allows you to customize deduplication and display settings, can automatically download some PDFs, and allows bulk uploads of PDFs to Covidence for full text screening. 
  • Zotero merges duplicates throughout the library, which can sometimes make it difficult to keep track of numbers for your PRISMA flow diagram. The free version also limits you to a certain amount of storage, which may not be enough if you are conducting a large review or multiple reviews. Zotero can automatically download some PDFs and supports bulk uploads to Covidence for full text screening.
  • Mendeley does support bulk PDF uploads to Covidence for full text screening.


Importing articles to a citation manager

You'll need to export files from the databases into a citation manager of choice, remove the duplicate articles, and then export the remainder into Covidence.

Deduplicating your references

Before screening your articles, you should first remove any duplicate listings of citations (deduplicate) in a citation manager.  While you can often deduplicate in screening tools such as Covidence, they may have limited functionality for automatically identifying duplicates or for marking citations as duplicates during the screening process.

Other Tools

Search, Information Management and Screening Tools 

SR Toolbox: htp:// 


Systematic Review Accelerator: htps:// 


Citation Chaser: htps:// 


LitSearchr: htps:// 


Automated Systematic Search Duplicator (ASySD): htps:// 


Covidence: htps:// 


DistillerSR: htps:// 


Rayyan: htps:// 


SysRev: htps:// 


CADIMA: htps://