Evidence Synthesis: Managing & Screening References

Evidence synthesis searches may retrieve thousands or tens of thousands of references because they are broad searches meant to locate all relevant evidence. Databases with overlapping indexing may retrieve duplicates of the same articles. These records will need to be screened to identify eligible studies. Researchers must document details of the screening process as part of transparent reporting.

Next steps include:

• manage your records by deduplicating repeat records,
• screen each title/abstract,
• screen the full-text of the remaining records, and
• create a documenting flowchart.

Software can help facilitate these processes which can be among the most time-consuming stages of evidence synthesis.

Screening Rounds

• Title/Abstract Screening
  • Each record is examined for relevancy. Eligibility criteria is applied. Include studies that lack information but might be relevant. If exclusion criteria is evident, exclude the study in this stage.
• Full-Text Screening
  • Once full-text is retrieved, eligibility criteria is applied. Reasons should be provided for excluded studies at this stage.

Screeners

• Review teams should include least two screeners. An additional screener or a plan for resolving conflicts is needed.
• Prepare for screening by completing a pilot screen
• Screeners should work independently so as not to introduce bias

Screening software (scroll down for details)

• Covidence
• Rayyan

Create a PRISMA flow diagram to document the flow of studies through the screening process.

According to the PRISMA website, "the flow diagram depicts the flow of information through the different phases of a systematic review. It maps out the number of records identified, included and excluded, and the reasons for exclusions."

Example of a PRISMA flow diagram:

EndNote 21 is a reference management software provided by Midwestern University.

EndNote enables researchers to store and organize large numbers of references. EndNote is often used to de-duplicate references before records are moved to a screening software.

Rayyan is an alternative to Covidence. It is a free online tool aiding in the screening and coding of studies for systematic reviews.

MWU Librarians cannot retrieve full-text of articles for research teams, but will be glad to recommend an efficient workflow to acquire them.

1. Rethlefsen ML, Page MJ. PRISMA 2020 and PRISMA-S: common questions on tracking records and the flow diagram. J Med Libr Assoc. 2022;110(2):253-257. doi:10.5195/jmla.2022.1449