PICO is a structure you can use to create focused foreground questions. PICO helps to break down a clinical scenario and turn it into an answerable question that can be used to search for evidence. Foreground questions have three to four essential elements, usually a population, intervention (or 'indicator') and an outcome.
When using the framework, it's not necessary to use every category, the categories are simply there to guide you in forming a evidence-based question. Many clearly defined questions do not have a comparison or control to consider, so don't worry if this category isn't applicable for your topic.
PICO will make it easier to select the most important keywords to search upon and help you narrow the focus of your topic or question to get a manageable number of relevant search results. Click on the 'i' icons for each section to learn how you decide what information you should include in each section.