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Evidence Pyramid

The hierarchy of evidence is a core principal of Evidence-Based Practice (EBP) .

EBP hierarchies rank study types based on the rigour (strength and precision) of their research methods.  The higher up on the pyramid a study is, the higher the quality and the more useful it is for clinical decision making.

 

Filtered information (a.k.a. secondary research) refers to syntheses and summaries that appraises the quality of a study and recommend its application in practice.  Examples include systematic reviews, meta-analyses, and clinical practice guidelines.

Unfiltered information (a.k.a. primary research) refers to original research studies that have not yet been synthesized or aggregated. Examples include cohort studies, randomized control trials, and case-control studies.

You can find both types of sources in these databases: CINAHL, Medline, and SPORTDiscus.

 

Adapted from Evidence-Based Practice in Health, University of Canberra Library and Evidence-Based Practice Resources, McGill University Library

Some suggested databases

Example PICO(T) question

Let's consider the following research question:

In university basketball players with patellar tendinopathy, what is the effect of radial shock therapy compared with ultrasound on pain management?

Before you start searching, it is helpful to us the PICO(T) or PS tool to help identify the key aspects of your question. Consider as well if there are any possible synonyms/related terms for each aspect of your question.

PICO Key terms synonyms & related terms Subject Headings
Population/problem (P)

patellar tendinopathy

 knee pain  
Intervention/Exposure (I/E)

radial shock wave

   shockwave therapy
Comparison (C) ultrasound sonogram? ultrasonography
Outcome (O)

pain management

 pain relief analgesia

Search techniques

Creating Searches with your keywords and database operators

Search different spellings and plural/singular

An asterisk (*) or truncation symbols means I don't care how it ends  

e.g. behav*

  • In this example, the database would search "behavior" and "behaviour" in both their singular and plural forms, as well as "behavioural" and "behaving"

Search phrases

Use quotation marks " " to search for a particular phrase  e.g. "pain management"

Proximity searching

Proximity searching lets you search for two words near each other e.g. ankle N2 sprain* will look for those words within two words of each other in any order

Using AND/OR

Avoid typing sentences into the search box. Always use AND or OR between different ideas:

  • AND (if you want all the words to appear in your search results) e.g. "drug use" AND athletes
  • OR (if you don't care which word shows up) e.g. college OR university

NOTE: These strategies work in MOST databases, but some databases use different symbols. Check the help features of the database you are using, or contact the Library Service Desk for help.

Keywords vs. Subject Headings

Keywords Subject headings

Natural language words that describe your topic

Pro: Easy to combine terms

Pro: Can search for them anywhere in the source

Con: Can be difficult to narrow results

Con: Might retrieve irrelevant results

Pre-defined vocabulary that describes your topic

Pro: Can quickly rule out irrelevant sources

Pro: Often retrieves more accurate results

Con: Harder to combine terms (need to know which terms exist)

Con: Doesn't always find the most recent articles

You can improve your search results by combining your keywords with the subject headings that each database applies to articles. These headings are added in order to tag articles that contain specific content, making them easier to find. 

In PsycINFO, the subject headings are called APA Thesaurus of Psychological Index Terms

In Medline/PubMed, the subject headings are called MESH

In CINAHL, the subject headings are called CINAHL headings

In SportDiscus, the subject headings can be found in the Thesaurus.

 

Example: 

You Keyword Database Subject Heading
cancer neoplasms (in Medline)
concussion brain concussion (in SPORTDiscus)
therapy therapeutics (in SPORTDiscus and Medline)

 

A great way to find additional articles on a topic is to follow citations in articles you have already found.

Strategy 1: Review the references of relevant articles you've found

Rubio, C., Osca, A., Recio, P., Urien, B., & Peiró, J. M. (2015). Work-family conflict, self-efficacy, and emotional exhaustion: A test of longitudinal effects. Journal of Work and Organizational Psychology, 31(3), 147–154. https://doi.org/10.1016/j.rpto.2015.06.004

Copy and paste titles from this list into LibrarySearch or Google Scholar to find them.

 

Strategy 2: Use Google Scholar or Scopus to find out who cited the articles you've found

Google Scholar

Scopus