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Systematic Reviews

Screening Process

1. Introduction to the Screening Process

The screening process is a crucial step in conducting a Systematic Review. Since a comprehensive search will always yield more results than you an include in your final analysis, it's essential to outline your screening process ahead of time. such as that involved in a Systematic Review will always return more results than you will include in your final appraisal. You should also consider using available tools that could help you with the screening process.

2. Role of Inclusion and Exclusion Criteria

The screening process, guided by the inclusion and exclusion criteria established in your review protocol, serves the crucial purpose of eliminating irrelevant results. To minimize both bias and the risk of discarding pertinent studies, it is customary for two or more independent reviewers to be involved in the screening process. With a substantial number of results, the review task can be distributed among team members while ensuring each study undergoes screening by at least two reviewers.

3. Tools for the Screening Process

Several tools can facilitate the screening process, ranging from general reference management tools such as EndNote or Mendeley, to dedicated screening tools such as Covidence, Rayyan, EPPI Reviewer, ASReview LAB, Abstrackr or Screenatron (part of of the Systematic Review Accelerator). The choice of tool will depend on individual preference and the complexity of the review.

4. Two-Step Screening Process

The screening process typically involves a two-step approach with the participation of two or more reviewers.

  • First pass: Reviewers assess titles and abstracts of each item, swiftly eliminating clearly irrelevant material
  • Second Pass: Reviewers thoroughly examine the full text of remaining items to determine their eligibility based on the predefined criteria outlined in the review protocol.

The process should be well-documented, including reasons for exclusion. You should have an agreed method for resolving any disputes regarding inclusion.

5. Documenting the Screening Process

It is important to keep a detailed record of the screening process. The number of items that were included and excluded at each step should be noted. This record will serve as a complete account of the decision-making process and will help ensure the review methodology is transparent.

6. Assessing Bias and Quality Appraisal

After identifying the potential items for inclusion in the review, it is necessary to assess their quality and address any biases contained in the items. This can be done through the use of tools such as AMSTAR or a Critical Appraisal Skills Programme (CASP) checklist. These tools prepare the groundwork for the subsequent stages of data extraction, synthesis and interpretation.