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Evidence Based Practice

Hierarchy of Evidence

Hierarchy of evidence

Adapted from: DiCenso, A., Bayley, L., & Haynes, R. B. (2009). ACP Journal Club. Editorial: Accessing preappraised evidence: fine-tuning the 5S model into a 6S model. Annals of Internal Medicine, 151(6), JC3-2, JC3-3.

Where to Acquire

Summaries (Evidence-based textbooks & Guidelines)
Synthesis (Systematic Reviews)
Synopsis of Studies (Evidence-based abstraction journals)


Studies (Original Articles)
Background (Textbooks)

PubMed Tips & Tricks

Improve results by getting to know PubMed! Click through the tabs above to learn more about powerful PubMed features.
PubMed homepage
Click on the tabs above or links below to learn more about:
  1. Clinical Queries: Easily filter results by type of question (therapy, diagnosis, etc.) and type of study (RCT, cohort, etc.).
  2. MeSH (Medical Subject Headings): Find the best terms to locate articles on topic.
  3. Advanced: Return to previous searches or combine searches using the history.
  4. My NCBI: Create your account to unlock many useful features such as saving searches and collections of citations.
Have a clinical question, and need a quick answer? Try PubMed's Clinical Queries Tool!
Type your search into the box, click search, and then use the options below to narrow in on specific question/study types.  
PubMed Clinical Queries

Medical Subject Headings (MeSH) are standardized terms assigned to every citation added to PubMed to highlight the topics covered in the article.  Understand MeSH and make them work fo you!

Here's a list of one article's list of MeSH Terms:

Article Mesh terms


You can directly search for MeSH terms to use in your search. 

Mesh search

1) Change the dropdown to MeSH before searching for a single term.

2) Quickly narrow in on a topic by selecting a sub-heading.

3) Focus your search even more by selecting the option to Restrict to MeSH Major Topic.

4) Take a look at the term trees, which show broader and narrower terms.  Note that any term below the one you search for will be included.

5) Use the options on the right to search in PubMed for the terms you find in the MeSH database.


Be sure when you search PubMed directly to check the Advance Page and review the details on how your search was translated.  Did it find MeSH terms?  Do they make sense?  If not, try looking at some articles to see what MeSH were assigned and then add those terms to your search.


Use the Advanced page to review your search history, review how a search was translated (1), return to searches (2), combine searches (3), or even start a new search (4).

advanced pubmed

My NCBI is your own personal account in the NCBI system.  

Create an account using an account you already own such as Google, Microsoft, or Facebook. 

NCBI login


Once you have an account you can do many things, such as: 

  1. Customize settings (i.e. have search terms highlighted in results; set to automatically show abstracts and 100 citations at a time)
  2. Save searches that you want to keep up on and set up email alerts
  3. Save citations to collections for future referral or to share with others
  4. Return to recently run searches

NCBI homepage