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Expert Keyword Searching

Using Limits and Inclusion/Exclusion Criteria

Once you have some search results, you will need to decide which articles you will actually use in your literature review. This can be done using filters/limits in the databases, applying inclusion/exclusion criteria, and appraising the articles.

Filters and Limits

Filters and limits (the name varies by database) are tools the database provides to help you narrow your search results. Different databases offer different filters, but these are some of the more common ones you'll find.

  • Publication year
  • Language of the article
  • Age of study subjects
  • Study design

Inclusion and Exclusion Criteria

Your search terms and the filters/limits you apply are generally not enough to narrow your results to the most relevant and highest quality studies for your project. The final step to selecting these studies is to apply your inclusion and exclusion criteria. Basically, these are the reasons why you keep (include) or reject (exclude) articles as you look through the results, reading titles and abstracts (and sometimes the whole article)

Examples of types of Inclusion/Exclusion Criteria

  • PICO(T) elements - if one of the main elements of your topic does not match those of the study, you may need to exclude it
  • Age - if you can't use a filter/limit to exclude studies that do not focus on the age group you require, you may need to exclude those studies yourself.
  • Setting - i.e. home, acute care, assisted living facility
  • Study Design - sometimes a filter/limit doesn't exist for the study design you're interested in; in that case you'll need to look through articles to find that detail yourself.
  • Number of subjects - do you have a minimum study group size? 
  • Study drop-out rate 

Limits and Inclusion Criteria

Filters and Limits

Inclusion and Exclusion Criteria