PICO is just an acronym.
PICO helps you remember which key concepts must be identified when formulating a research question and which concepts to include in a search strategy to retrieve the most relevant articles that will answer your research question and to have confidence that you identified any published research reports that exist.
Formulating a PICO question | Tutorial by University Libraries, Penn State
P = Patient Problem / Population
Commonly a population with a topic of interest, e.g. obese adolescent, diabetic adolescent
I = Intervention
Includes therapies, treatments, procedures, tests
C = Comparison
Includes interventions, therapies, procedures, tests, treatments, placebo
O = Outcome
Once you have identified keywords that MUST be included in your search in order to retrieve relevant articles, a rigorous search across multiple databases,and a search by author's identified as researchers on your topic will help to confirm whether or not relevant research has been reported on your specific PICO question.
Below find a sample formulation of a research question not yet fully developed and refined. It is a good beginning, but too board. Background reading will inform the novice on how to further add the necessary specifics to this question. Keep a list of keywords and their synonyms as develop a search strategy for use in the research databases.
Review the following research question. What elements are identified? What is the population with topic of interest, intervention, comparison intervetion or placebo, and the measured outcome?
PICO Question #1 - Broadly stated with no type of exercise intervention and no outcome/measurement defined.
Does exercise help the obese adolescent?
PICO Question #2 - PICO elements defined with specific type of exercise and outcome/measurement.
Is resistance training more effective than aerobic exercise in promoting weight loss in the obese adolescent
Researchers identify a specific population, therapy/intervention/procedure/test, sometimes a comparison with another intervention or placebo, and the specific desired outcome that they hope will be obtained when using the intervention and comparative placebo. A choice of a valid study design will factor in all of these elements and incorporate some kind of measurement of outcome and results.