Medicine Subject Guides: Screening

Two-step screening is a method commonly used in systematic reviews to ensure rigorous and reliable screening of studies. It involves having two independent reviewers independently assess the titles and abstracts of studies identified during the initial search, followed by a second round of independent full-text assessment.

Here's how the two-step screening process typically works:

Step 1: Title and Abstract Screening

• Two independent reviewers assess the titles and abstracts of the identified studies against the predetermined inclusion and exclusion criteria.
• Each reviewer makes an independent decision on whether a study should be included or excluded based on the initial screening.
• Discrepancies or uncertainties are resolved through discussion, consensus, or by involving a third reviewer if needed.

Step 2: Full-Text Assessment

• After completing the title and abstract screening, the reviewers move on to the full-text assessment stage.
• The same two independent reviewers independently evaluate the full-text articles of the studies that passed the initial screening.
• Each reviewer determines whether a study meets the inclusion criteria or should be excluded based on a detailed examination of the full-text content.
• Again, any discrepancies or uncertainties are resolved through discussion, consensus, or by involving a third reviewer if required.

The purpose of two-step screening is to enhance the reliability and accuracy of the study selection process in a systematic review. By involving two independent reviewers, it helps minimize potential biases and increases the likelihood of capturing relevant studies while reducing the risk of excluding important ones.This approach is considered good practice in systematic reviews to ensure the inclusion of high-quality evidence and to maintain transparency and objectivity throughout the screening process.

The PRISMA Flow Diagram can be utilized to document the study selection process in your systematic review.

The PRISMA flow diagram provides a visual representation of the screening process in a systematic review. It begins by documenting the total number of articles identified and subsequently tracks the selection process, transparently reporting the decisions made at each stage. At each step, the diagram records the number of articles included or excluded. During the full-text assessment stage, it is crucial to include the reasons for excluding articles to maintain transparency and clarity.

See the Prisma2020 site for more information.