Basics of Systematic Reviews

After your team has finished the literature search and collected all citations, the next step is screening.  The main purpose of this step is to remove any studies, articles, and documents that do not meet the inclusion criteria.  The process is completed in 2 phases: a title and abstract screening, then a full-text screening.

During this step, you and your team will:

1. Use a systematic review screening tool (like Covidence or Rayyan) to organize articles.
2. Select 3 team members to serve as reviewers.  You need an odd number of reviewers in order to resolve disputes.
3. Read the title and abstract of each article.
4. Reviewers will vote to include or exclude the article in your review based on the predefined inclusion/exclusion criteria.
   1. All voting should be blinded.  This means that the reviewers should not see how other members cast their votes, which helps prevent bias.
   2. For each reference, the reviewer will make one of the following selections:
      1. NO: This reference does not meet our inclusion criteria and should not be included in the review.
      2. YES: This reference seems to meet our inclusion criteria.  It should move on to the full-text screening stage.
      3. MAYBE: Not enough information is available in the title or abstract to make a decision. (this selection moves the reference to the full-text screening stage, where it can be determined if inclusion criteria are met within the content of the article).
5. Resolve disputes with your teammates.
   1. If one reviewer votes to include an article and another votes to exclude it, a third reviewer will serve as the tie-breaker.
6. Locate the full text of each article you plan to include.
7. Read the full text of included articles to determine if they are relevant.

The two most popular screening tools are Covidence and Rayyan. 

During the screening process, keep in mind that:

• Screening is the lengthiest and most work-intensive piece of SR
• Screening is critical for a high‐quality systematic review
• Searches can easily result in thousands of articles to be screened