Phillips School of Nursing Information Commons: PICO & Searching
Literature Searching with PubMed, Scopus, and CINAHL through Levy Library
The PICO Framework
The PICO framework is the most commonly used model for structuring clinical questions because it captures each key element required for a focused question. PICO stands for:
- Patient or problem
- Intervention or exposure
- Comparison or control
- Outcome(s)
The table below illustrates ways in which problems, interventions, comparisons and outcomes vary depending on the type (domain) of your question.
| Question Type | Patient or Problem | Intervention or Exposure | Comparison | Outcome Measures |
|---|---|---|---|---|
| Therapy | The patient's disease or condition. | A therapeutic intervention, ex., a drug, surgical intervention, medical advice. | Standard care, another intervention, or placebo. | Ex: Mortality rate, complications, disease recurrence. |
| Diagnosis | The target disease or condition. | A diagnostic test or procedure. | The current "reference standard" test for the problem. | Measures of the test utility, ex., sensitivity, specificity. |
| Prognosis | The main prognostic factor or clinical problem in terms of its severity and duration. | The intervention or exposure of interest, ex. a disease, drug, or time. |
Standard care, another intervention, or placebo for interventions. Absence of exposure for exposures. May not be applicable, particularly if exposure of interest is time. |
Ex: Rates of survival, mortality or disease progression. |
|
Etiology or |
Your patient's risk factors, current health disorders or general health condition | The intervention or exposure of interest, ex. a disease, drug, or time, including some indication of the strength (dose) of the risk factor and the duration of the exposure. |
Standard care, another intervention, or placebo for interventions. Absence of exposure for exposures. May not be applicable. |
Ex: Disease incidence, rates of disease progression or rates. |
| Prevention | The patient's risk factors and general health condition. | A preventive measure, e.g., a medication or a lifestyle change. | Absence of preventive measure. May not be applicable. | Ex: Disease incidence, mortality rate, days lost from work. |
When constructing your PICO question, a few important points to bear in mind:
- Your patient is a member of a population as well as a person with (or at risk for) a health problem.
- Factors to consider include age, sex, comorbid conditions, past medical history, socioeconomic status or other demographic variables, as these factors may impact your patient's risk level.
- You need to assess what reasonable clinical study population your patient could be part of. For example, if your patient is a 73 year old woman, "73 year old women" or "women in their 70s" is too specific because it is highly unlikely that clinical researchers would design a study that would exclusively enroll women in their 70s. Depending on the nature of your question, a reasonable population might be something like "post-menopausal women" or "older adults."
- Outcomes must be measurable and ideally measure clinically important outcomes rather than surrogate markers such as laboratory test results.
The Question Statement
Once you have identified the main elements of your question using the PICO format, it will be easier to write your question statement. To improve the flow of the question statements, we have placed the comparison after the outcome in the examples below.
| Question Type | Patient or Problem | Intervention or Exposure | Outcome | Comparison |
|---|---|---|---|---|
| Therapy | In patients with hypertension and at least one additional cardiovascular disease risk factor | Does tight systolic blood pressure control | Lead to lower rates of myocardial infarction, stroke, heart failure, and cardiovascular mortality | Compared to conservative control? |
| Diagnosis | Among asymptomatic adults at low risk of colon cancer | Is fecal immunochemical testing (FIT) | As sensitive and specific for diagnosing colon cancer | As colonoscopy? |
| Prognosis | Among adults with pneumonia | Do those with chronic kidney disease (CKD) | Have a higher mortality rate | Than those without CKD? |
| Etiology or Harm | Are women | With a history of pelvic inflammatory disease (PID) | At higher risk for gynecological cancers | Than women with no history of PID? |
| Prevention | Among adults with a history of myocardial infarction | Does adherence to a mediterranean diet | Lower risk of a second myocardial infarction | Compared to those who do not adopt a mediterranean diet? |
Literature Searching
Successful Searching:
Simple search statements include only two to three core concepts. Beginning EBM searchers often make the mistake of trying to incorporate every concept from their PICO analysis in their search query — which often results in few or no search results. In general, start your search with no more than three search concepts. These concepts should reflect your question's most important PICO elements. To help set priorities, some suggest underlining the key terms in your search statement and others recommend listing them in rank order of importance
Once you have identified the main concepts of your question, you'll need to choose good search terms to represent those concepts. Unsuccessful or incomplete searches are often caused by using overly specific terms or subject headings, or by the failure to specify alternate terms when the initial search fails.
Search Tip: Start with broader concepts
For example, begin searching with cardiac arrhythmia AND anticoagulation. Then, if you retrieve too many results, use more specific concepts (atrial fibrillation AND warfarin).
Search Tip: Identify alternative ways to express your main concept
Connect synonyms or related concepts with OR (e.g., warfarin OR anticoagulants OR coumarins).
Boolean Operators
Boolean Operators link concepts and are used to broaden or narrow your search. Briefly, here's how they work:
AND - finds results with both keywords. AND narrows your search. The advanced search in most databases defaults to automatically use AND between the search boxes.
- For example, in a search for gene AND expression, you will find records where both the word gene and the word expression appear.
OR - finds results with either of the keywords. OR broadens your search.
- Drug Effect OR Drug Effects OR Adverse Effects etc. will search for all terms.
NOT - excludes items that use the keywords. NOT narrows your search.
- pregnancy NOT teen
Using Boolean's: Connecting Terms
For best results, only use the OR within a search box. The AND is placed automatically between the search boxes.
An example search for evidence-based practice in nursing research might look like this:
First search box: nursing research OR nursing education
Second search box: evidence-based practice OR evidence-based medicine
Truncation & Phrase Searching
Phrase Searching:
Enclose the phrase using double quotation marks (i.e. "shift handoff") in order to find citations that have those words in the exact order. Gets fewer citations.
- patient falls finds 2,619 citations
- "patient falls" finds 483 citations
Truncation is a search method in which symbols are used in place of letters or words to help you broaden your search (i.e., get more citations).
The asterisk (*) represents any group of characters, including no character. Use it at the end of the root of your term.
- prevent* finds prevent, preventative, prevented, preventing, etc.
- smok* finds smoke, smokeless, smoker, smoking, etc.