How to Conduct a Literature Review (Health Sciences)

A well-formulated research question:

• starts your entire search process
• provides focus for your searches
• guides the selection of literature sources

Question formats are helpful tools researchers can use to structure a question that will facilitate a focused search. Such formats include: PICO, PEO, SPIDER, and COSMIN.

The PICO format is commonly used in evidence-based clinical practice. This format creates a "well-built" question that identifies four concepts: (1) the Patient problem or Population, (2) the Intervention, (3) the Comparison (if there is one), and (4) the Outcome(s).

Example: In adults with recurrent furunculosis (skin boils), do prophylactic antibiotics, compared to no treatment, reduce the recurrence rate? (Cochrane Library Tutorial, 2005)

The PEO question format is useful for qualitative research questions. Questions based on this format identify three concepts: (1) Population, (2) Exposure, and (3) Outcome(s).

Example: In infants, is there an association between exposure to soy milk and the subsequent development of peanut allergy?

The SPIDER question format was adapted from the PICO tool to search for qualitative and mixed-methods research.  Questions based on this format identify the following concepts: (1) Sample, (2) Phenomenon of Interest, (3) Design, (4) Evaluation, and (5) Research type.

Example: What are young parents’ experiences of attending antenatal education? 

Search for (S AND P of I AND (D OR E) AND R) (Cooke, Smith, & Booth, 2012).