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Systematic Reviews and other Evidence Syntheses

Conduct Screening

Use the inclusion and exclusion criteria defined in your protocol to remove studies that are not relevant to your topic.  The first phase of study selection is the title/abstract screening, then the full text must be retrieved and screened to decide if the study should be included in your review.  The standards dictate that at least two independent reviewers screen studies, resolving areas of disagreement by consensus or a third party who is an expert in the field.

Title/Abstract vs Full Text Screening

Study selection is typically a multi-stage process in which potentially eligible studies are first identified from screening titles and abstracts then assessed through full-text review. Title/Abstract screening allows reviewers to quickly exclude large a large quantity of articles that are clearly off-topic due to content, study type, language, or other previously determined exclusion criteria. The full-text search is then used to review the full content of all remaining articles to determine validity for inclusion. 

Title/Abstract Screening

  • Completed before full-text screening
  • Reviewers only review title and abstract to determine inclusion or exclusion
  • Used to quickly eliminate articles that are clearly not topical, are an excluded study type, are in an excluded language, etc.

Full-Text Screening

  • Completed after title/abstract screening
  • Involves reading the entire article to determine inclusion/exclusion
  • Must provide reasons for exclusion in full-text screening

Screening Tools

Screening tools are used to help organize, manage, and track the large volume of articles that are returned in systematic review searches. It is important to remember that all screening tools used (Covidence, Endnote, etc.) must be cited and described in the review methods

Often, multiple tools will be used concurrently. For example, citations may be stored in Endnote, but deduplicated and screened via Covidence. Therefore, it's important to document what tools are used and how they are used during the screening process so it can be accurately represented in your methodology.

Deduplication Tools


A deduplication, screening, extraction and risk-of-bias assessment tool.

  • More sensitive than Endnote
  • Commonly quicker deduplication process than Endnote
  • Tags RCTs and non-RCTs
  • May miss some duplicates
  • Clinical Trials data and other non-article citations need to be edited in EndNote before moving to Covidence.



A citation management tool with a built-in deduplicator

  • All citation management and deduplication can be done using this one tool
  • Thorough deduplication requires lots of time and many searching iterations.
  • Does not rank citations based on likelihood of duplication
  • Up to reviewer to do most work by hand

Full Text Retrieval


Not being able to access the full text of an article is not an appropriate reason to exclude the article. Request any articles you cannot access through your library's Interlibrary Loan (ILL) department in order to complete a full-text screening. 

Mitigating bias in your screening