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Systematic review searching

A resource to assist Flinders University staff and students undertaking systematic reviews

Conceptualising the search

An overview of the process described across these tabs is available for download here:

Formulating the question

The systematic review question is formulated a priori and tested during the scoping phase.
A standard formula for structuring the review question is PICO(S) for quantitative questions and SPIDER for qualitative ones.

PICOS for quantitative questions


Patient, Population,
or Problem

(or exposure)
(or control)
Outcomes of interest Study designs
Who are the patients
or population groups of interest?
What is the problem?
What is being done
to them?
How frequently?
By what means? What are they exposed to?
Are we comparing
the intervention to something else?
A control?
A placebo?
Another  treatment?
No intervention?
Which measurable
outcomes are relevant
to our question? (both positive and negative)
Which study designs
(e.g. RCT)
are appropriate for answering my question?




An example PICOS

Is high dose amoxicillin more effective than a watch-and-wait approach to treating children with otitis media (middle ear infection)?


 Population:   Children with otitis media
 Intervention: Amoxicillin (high dose)
: Doing nothing (a watch-and-wait approach)
 Outcome(s): Clinical cure at the end of treatment (i.e. bacterial eradication),
 time to  cure, adverse side-effects.
 Study design(s):  A Randomised Controlled Trial (RCT) would be the
 strongest  design for answering an interventional therapy question of this type.

SPIDER for qualitative questions

Sample Phenomenon of Interest Design Evaluation Research type
Who are the people you are interested in studying? What do you hope to understand? It is a behaviours, attitudes, beliefs, or individual experience? What research methods or theoretical frameworks are appropriate? What outcome measures are you interested in? Three apply here: qualitative, quantitative, and mixed methods.

An example SPIDER

What are the challenges faced by mothers living with multiple myeloma in remote and rural areas of Australia?

 Sample: Mothers living with multiple myeloma
 Phenomenon of Interest: Challenges and barriers encountered by virtue of living remotely in Australia
Questionnaires, surveys, interviews, focus groups, case studies, or observational studies
Evaluation: Views, experiences, opinions, attitudes, perceptions, beliefs, feelings, knowledge, or understanding
Research type: Qualitative or mixed methods

From PICO to a Logic Grid

Once you have clarified your question by creating a PICOS or SPIDER structure for it, transfer the significant concepts in your PICO/SPIDER to a Logic Grid.

The Logic Grid will help you:

  • identify the concepts in your question which need to searched on for your search to have a minimum level of precision
  • clarify which concepts can be left out of the search, or added later if required to improve precision
  • prepare for finding appropriate and useful synonyms, acronyms, variant spellings etc. for each concept.

From PICOS to Logic Grid

Watch the video below for how to translate a PICO to a logic grid.

The study designs best suited for answering your question will depend on the type of question being asked.

Common question types:

  • Therapy: how to select treatment to offer patients that do more good than harm and that are worth the efforts and costs of using them.
  • Diagnosis: how to select and interpret diagnostic tests in order to confirm or exclude a diagnosis, based on considering their specificity, sensitivity, likelihood ratios, expense, safety, etc.
  • Prognosis: how to estimate the patient's likely clinical course over time and anticipate likely complications of disease.
  • Etiology/Harm: how to identify causes for disease.
  • Prevention: how to reduce the chance of disease by identifying and modifying risk factors and how to diagnose early by screening.
  • Qualitative: how is the person experiencing what is happening to them? What are their perceptions, beliefs, attitudes?

Best designs for specific question types:

Type of Question  Best Type of Study
   Therapy RCT -> cohort -> case control -> case series
   Diagnosis                 prospective, blind comparison to a gold standard  
   Etiology/Harm RCT -> cohort -> case control -> case series
   Prognosis Cohort study -> case control -> case series
   Prevention RCT -> cohort study -> case control -> case series

Methodological search filters for limiting a search by study design



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