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Systematic Reviews & Evidence Synthesis Methods

This is a guide to understanding systematic reviews and other evidence synthesis methods. Links to resources and information about the Libraries' Systematic Review Service is included.

Developing Your Question

Developing your research question is one of the most important steps in the review process. At this stage in the process, you and your team have identified a knowledge gap in your field and are aiming to answer a specific question, such as

  • If X is prescribed, then Y will happen to patients?

OR assess an intervention

  • How does X affect Y?

OR synthesize the existing evidence 

  • What is the nature of X? ​

​​Whatever your aim, formulating a clear, well-defined research question of appropriate scope is key to a successful review. The research question will be the foundation of your review and from it your research team will identify 2-5 possible search concepts. These search concepts will later be used to build your search strategy. 

PICOT Questions

Formulating a research question takes time and your team may go through different versions until settling on the right research question.  A research question framework can help structure your systematic review question.  

PICO/T is an acronym which stands for

  • P       Population/Problem
  • I        Intervention/Exposure
  • C       Comparison
  • O      Outcome
  • T       Time

Each PICO includes at least a P, I, and an O, and some include a C or a T. Below are some sample PICO/T questions to help you use the framework to your advantage. 

For an intervention/therapy

In _______(P), what is the effect of _______(I) on ______(O) compared with 

Visual representation of the PICO/T Question Framework. text reads: P - Population/Problem; I - Intervention/Exposure; C - Comparison; O - Outcome; T - Time

_______(C) within ________ (T)?

For etiology

Are ____ (P) who have _______ (I) at ___ (Increased/decreased) risk for/of_______ (O) compared with ______ (P) with/without ______ (C) over _____ (T)?

Diagnosis or diagnostic test

Are (is) _________ (I) more accurate in diagnosing ________ (P) compared with ______ (C) for _______ (O)?

Prevention

For ________ (P) does the use of ______ (I) reduce the future risk of ________ (O) compared with _________ (C)?

Prognosis/Predictions

Does __________ (I) influence ________ (O) in patients who have _______ (P) over ______ (T)?

Meaning

How do ________ (P) diagnosed with _______ (I) perceive ______ (O) during _____ (T)?

Melnyk B., & Fineout-Overholt E. (2010). Evidence-based practice in nursing & healthcare. New York: Lippincott Williams & Wilkins.

References

Ghezzi-Kopel, Kate. (2019, September 16). Developing your research question. (research guide). Retrieved from https://guides.library.cornell.edu/systematic_reviews/research_question