As we saw on the previous page, the first step in the evidence-based practice process is to formulate a clinical question.
The clinical question should be relevant to the patient or the problem and formulated in such a way as to help with the search for an answer. Using a framework such as PICO or SPIDER can help you to work out the key elements of your question and know which concepts to combine in your literature searching.
There are many other frameworks that can be used for different types of questions. You should use the framework that best suits your type of question.
See our Systematic Review Guide - Identifying an answerable question for more detailed information.
The PICO framework is commonly used to formulate the clinical question. Each of the 4 letters identifies a key component of the question:
| P | Patient/Population/Problem | Start with the patient, or group of patients, or problem. |
| I | Intervention | What is the proposed intervention? |
| C | Comparison | What is the main alternative, to compare with the intervention? (May be just the status quo) |
| O | Outcome | What is the anticipated or hoped-for outcome? |
PICO is commonly used when one intervention is being compared with another, or with no intervention at all.
Sometimes this is expanded to PICOTT, which adds on extra letters for:
T Type of Question - Such as a diagnosis, prognosis, therapy, aetiology/harm, or prevention question
T Type of Study - Includes the study design that would best answer the question: randomised controlled trial; cohort study; case controlled study; case series; case series; case report etc. See also Levels of Evidence.
There's a good outline of this, including some self-testing, on the National Library of Medicine's PubMed information site: Using PICO to frame clinical questions.
Here is an example of a clinical problem formulated using PICO:
"I work in an aged care facility where urinary tract infections are a common problem. I've heard that cranberry juice can help prevent UTIs. I wonder if there's any evidence for that and whether it might help our patients?"
| P | Patients in aged care homes |
| I | Cranberry Juice |
| C | No intervention (status quo) |
| O | Prevention of UTIs |
Once you've worked out your PICO, your question becomes clearer:
“Does cranberry juice help reduce urinary tract infections in people living in aged care facilities?”
The SPIDER tool can be used when dealing with qualitative research questions, that is, when the research is about attitudes and experiences rather than quantitatively measurable data. It focuses less on the intervention and more on the design of the study, and deals with "samples" rather than "populations".
| S | Sample | The group of participants in qualitative research |
| PI | Phenomenon of Interest | The how and why of behaviours and experiences |
| D | Design | How the study was devised and conducted |
| E | Evaluation | Measurement of outcome might be subjective and not necessarily empirical |
| R | Research Type | Qualitative, or quantitative, or mixed? |
Using the same example as above, what if you were more interested in a qualitative study of the problem?
| S | Sample | Patients in aged care homes |
| PI | Phenomenon of Interest | Cranberry juice for the prevention of UTIs |
| D | Design | Survey |
| E | Evaluation | Experiences |
| R | Research Type | Qualitative |
Now your clinical research question could be structured this way:
What are the experiences of patients in aged care homes with the use of cranberry juice for UTIs?
Again, notice that the phrasing of the question is now clear, and so is a much better start for your searching. You'll also notice that the final question formulated is very different to the one produced using the PICO strategy. You should use the strategy best suited for your chosen Clinical Question.
Evidence-Based Medicine in Practice
Professor Paul Glasziou from the University of Oxford's Centre for Evidence-Based Medicine (CEBM) talks about forming a PICO question.
Evidence-Based Practice: Step 1: Ask the Question (PICO)
Includes information on the different types of questions. (From the Medical University of North Carolina Libraries)
Evidence-Based Practice: What Type of Question
Information on PICO and SPIDER but also on other ways of structuring a research or clinical question. (From the University of Notre Dame Library, Australia)
Beyond PICO: the SPIDER tool for qualitative evidence synthesis
This article looks at using PICO and SPIDER as tools to help in literature searching.
Cooke, A., Smith, D., & Booth, A. (2012). Beyond PICO: The SPIDER tool for qualitative evidence synthesis. Qualitative Health Research, 22(10), 1435-1443. doi:10.1177/1049732312452938
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