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Evidence-Based Practice (EBP)

In addition to the basics of EBP and PICO, this guide answers questions about primary vs. secondary sources, where to look for evidence, and how to search to get the best results.

Selection Criteria

You may want to think about criteria that will be used to select articles for your literature review based on your research question. These are commonly known as inclusion criteria and exclusion criteria, and they set the boundaries for the literature review.

Inclusion and exclusion criteria are determined after formulating the research question but usually before the search is conducted (although preliminary scoping searches may need to be undertaken to determine appropriate criteria). It may be helpful to determine the inclusion criteria and exclusion criteria for each PICO component.

Be aware that you may introduce bias into the final review if these are not used thoughtfully. 

The same database filter can serve both functions; it's a matter of perspective. For instance, if articles must be published within the last 3 years, that is inclusion. If articles cannot be more than 3 years old, that is exclusion. 

Inclusion Criteria

Inclusion criteria are the elements of an article that must be present in order for it to be eligible for inclusion in a literature review. Some examples are:

  • Included studies must have compared certain treatments
  • Included studies must be a certain type (e.g., only Randomized Controlled Trials)
  • Included studies must be located in a certain geographic area
  • Included studies must have been published in the last 5 years

Exclusion Criteria

Exclusion criteria are the elements of an article that disqualify the study from inclusion in a literature review. Some examples are:

  • Study used an observational design
  • Study used a qualitative methodology
  • Study was published more than 5 years ago
  • Study was published in a language other than English