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Systematic Reviews: An Introductory Guide

Provides a brief overview of the systematic review process and lists resources used when conducting systematic reviews in healthcare.

Overview of the Systematic Review Process

A systematic review is a comprehensive analysis of all known evidence on a given subject. For a systematic review to be formally recognized by publishers it must include the following elements:

  • A clearly defined research question. The research question is often developed after performing preliminary research on the subject, ensuring that it is viable for a systematic review. Additionally, a search must be conducted to ensure no other systematic reviews exists on the topic.
  • Evidence of a rigorous search process. Systematic searching demands a carefully planned and exhaustive search strategy that will recall the maximum number of relevant results. Current standards require manuscripts to include an appendix of the exact search strategy used to find literature in at least one of the databases searched.
  • Inclusion and exclusion criteria. Not all evidence found during the search process will be relevant or appropriate to answer the research question. Clearly defined criteria must be used to decide which studies should and should not be included in analysis.
  • Critical appraisal of all included studies. For a study is to be included in the review, the quality of its evidence must be critically appraised by each member of the research team.

Littell, J. H., Corcoran, J., & Pillai, V. K. (2008). Systematic reviews and meta-analysis. New York;Oxford;: Oxford University Press

Structuring Research Questions

The PICO format is used in healthcare to help construct research questions used in systematic reviews

P= Patient, Population, Problem

I= Intervention

C= Comparison

O= Outcomes


RQ: What is the best diet for patients who have high blood pressure to prevent future heart attacks?

P= Patients with high blood pressure

I= Low sodium diet

C= Low fat diet

O= Heart attack prevention


How to search this in a general database:

"high blood pressure" AND ("low sodium diet" OR "low fat diet") AND "heart attack"


Other ways to breakdown or construct research questions

BeHEMoTh - identification of theories for realist synthesis questions

B Behaviour of interest
H Health context (the service, policy, program or intervention)
E Exclusions (for reviewers to exclude non theories)
MoTh: Models or Theories

CLIP –Health service management questions

C Client – at whom is the service aimed?
L Location – where is the service sited?
I Improvement – what do you want to find out?
P Professional – who is involved in providing/improving the service?


ECLIPS(E) – Health service management questions

E Expectation—what does the search requester want the information for?
C Client Group.
L Location.
I Impact—what is the change in the service, if any, which is being looked for? What would constitute success? How is this being measured?
P Professionals.
S Service—for which service are you looking for information? For example, outpatient services, nurse-led clinics, intermediate care.

MIP – Medical ethics questions

M Methodology  e.g. in-depth interviews or questionnaires
I Issues e.g. Healthcare Rationing or  end-of-life decision-making
P Participants e.g. physicians or patients


SPICE – Social science questions

S Setting – Where? In what context?
P Perspective – For who?
I Intervention (Phenomenon of Interest)– What?
C Comparison – What else?
E Evaluation – How well? What result?


SPIDER – Qualitative evidence synthesis

S Sample
PI Phenomenon of Interest
D Design
E Evaluation
R Research type