There is a range in quality of evidence available in the literature, with meta-analysis and systematic reviews being the very highest quality. As you move up the pyramid, the amount of literature decreases but its clinical relevance increases.
Sources of research may be either pre-appraised (summaries), primary literature or more anecdotal.
| Meta-analysis or Systematic Reviews | PubMed, CINAHL, Cochrane Library, SPORTDiscus |
| Critically-Appraised Topics | ClinicalKey, UpToDate |
| Critically-Appraised Articles | SPORTDiscus |
| Randomized Controlled Trials | Original articles (search CINAHL, PubMed, SPORTDiscus) |
| Cohort Studies | Original articles (search PubMed) |
| Case-Controlled Studies etc. | Original articles (search CINAHL, PubMed) |
| Background Info/Expert Opinion | Books, editorials (search print & e-books, CINAHL, PubMed) |
Always start an EBPT search looking for the highest level of evidence. If a meta-analysis is not available on the topic, look next for systematic reviews without statistical synthesis, next for randomized control trials, next for controlled comparison or case control studies, etc.
Meta-analyses: Methods of synthesizing the data from more than one study, in order to produce a summary statistic
Systematic Review: [tries] to answer a clear question by finding and describing all published, and if possible, unpublished work, on a topic. [It] uses explicit methods to perform a thorough literature search and critical appraisal of individual studies and uses appropriate statistical techniques to combine these valid studies (Booth & Brice, 2004).
Randomized Controlled Trial (RCT): are also called 'randomized clinical trial.' They involve the random assignment of subjects to groups that are then given different interventions to assess the effects of the interventions.
Controlled Comparison or Case Control Study: is an observational study in which the cases have the issue of interest
Descriptive Surveys: studies aimed at describing certain attributes of a population, specifying associations between variables, or searching out hypotheses to be tested, but which are not primarily intended for establishing cause-and-effect relationships or actually testing hypotheses.
Case Studies: describe a particular service or event, often focusing on unusual aspects of the reported situation or adverse occurrences, commonly have exploratory, descriptive, or explanatory purposes.
Booth A & Brice A (2004) Evidence Based Practice for Information Professionals: A Handbook. London: Facet Publishing.