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Knowledge Syntheses: A How-To Guide

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

Screening for Studies

Searching for studies is different than screening for studies. When screening potential articles to be included in a knowledge synthesis, keep these pointers in mind:

  • Think specifically, and at a granular level

  • Decisions are based on the specific characteristics of each study, as defined by the scope of your topic, and that will answer your question, eligibility criteria should be consistent with these characteristics

  • The process on how to handle uncertainty when screening should also be pre-determined, e.g. if the study is missing data, then include for now

  • Reviewers should have a high minimum of 90% agreement among them in their screening process

 

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First & second level of screening

Piloting the screening process

At every stage of screening, the screening process should be tested out to check what works and doesn't work for your specific team for this specific review. A small sample of all the articles to be screened are used to pilot a screening method and feedback from the reviewers are used to revise the screening method (inclusion/exclusion criteria details and definitions). This cycles until an agreeable method is found which then can be applied to the remaining articles.

First level of screening

In the first stage of screening, a pair of reviewers from the review team will independently scan titles and abstracts of articles that were retrieved from a comprehensive (i.e. multiple source) search, and make decisions whether to include or exclude articles. To do this in a streamlined, unbiased, and method-driven way, reviewers should adhere to the pre-defined eligibility criteria, or guidance form.

Keep these tips in mind during the first stage of screening:

  • Authors should generally be over-inclusive at this stage; a maybe is always a yes at this point
  • Screen for outcomes with caution if at all; they're poorly reported in the title and abstract. Save those for full-text!

  • Ask yourself: Is there enough information in the title and abstract to exclude this study at this stage, with absolute certainty?

Second level of screening

The second level of screening is a more rigourous, in-depth process in which the articles that were included in the first stage of screening are read in full-text. Similar to the first-level of screening, this is done independently by two reviewers from the review team, and the eligibility criteria that was used as a guideline for the first-level of screening is largely the same. However the second level of screening differs in these important ways:

  • The reason(s) for exclusion must be recorded and reported
  • You can now screen for outcome(s). Ask yourself: does the study report on the outcome(s) you're interested in?

  • Although the eligibility criteria is the same, it will require additional detail (clarifying questions may arise during the first stage of screening)

Content reused with permission from https://guides.library.utoronto.ca/c.php?g=713309&p=5104946