PBHL575: Epidemiological Research for Public Health

Use frameworks to avoid falling down the information rabbit hole.

Frameworks also help

• Identify searchable parts of a question
• Refine results
• Focus review process to relevant results

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There are several well-known frameworks (PICO, PEO) that you can use to help create and refine your search process (these are illustrated below). At their core, frameworks help identify the searchable parts of your question and how/when to incorporate them in the search process. 

One example might be to identify WHAT you are interested in + WHO or WHERE or WITH WHAT you are interested in it occurring/happening + a certain outcome of when the WHAT and WHO/WHERE/WITH WHAT are combined. You can add more columns if your research question is more complex or there are more co-existing factors.

• Create three columns and write down the parts of your research question that relate to each piece of this informal framework
• For each column, identify synonyms for your key terms
• For each column, if possible, write down more broad and more narrow terms - this will be helpful when you refine your search after reviewing preliminary results. If you do need more results, you can add or substitute broader terms; if you need to narrow down your results, you can add or substitute narrower terms. 
• Depending on your research question, it may not be necessary to add in key terms related to the Outcome at first. You can always start searching A + B first, then adding in Outcome-related key terms after reviewing the results.

Start searching! 

• In general, it can be good to start broad, then narrow down your search after seeing what literature exists on a topic and what kind of results you get.
• Connectors (AND, OR): connect synonyms with OR and columns (terms relating to different parts of your question) with AND. For example: 

topic a OR synonym OR synonym OR synonym

AND

topic b OR synonym OR synonym

AND

outcome key term

• Narrow down your search by adding or substituting key terms, activating filters, focusing on a specific article or study type, or mixing search fields (keywords, subject terms, and keywords isolated to title or title/abstract).

PEO is another framework that is especially useful when investigating a prognosis or likelihood of developing a certain condition as a result of a pre-existing condition or exposure. 

Patient/Population:  how would you describe the patient or population of interest? 

Exposure:  what pre-existing conditions does the patient/population have or what has the patient/population been exposed to?

Outcome:  the outcome of interest; unlike in PICO, the outcome is almost always used in the search terms with the PEO framework

PICO is a popular framework for clinical questions, especially those relating to therapy (intervention) effectiveness.  This framework helps identify discrete and searchable aspects of a situation where a patient or population has a certain condition and the outcome of interest is related to a therapy or intervention. 

Patient/Population:  how would you describe the patient or population of interest? 

Intervention:  what therapy or intervention do you want to investigate exposing the patient or population to?

Comparison:  (optional) (may be null)  what therapy or intervention do you want to compare the primary intervention to?

Outcome:  the outcome of interest; may be used in search terms or during results review

Time:  (optional)  may be a limiter or used during results review (the past 5 years, for example)

Study:  (optional)  may be a limiter or used during results review (preferring systematic reviews, meta-analyses, and RCTs over other study designs, for example)