PICO is a format for developing a good clinical research question prior to starting one’s research. It is a mnemonic used to describe the four elements of a sound clinical foreground question. (Yale University’s Cushing/Whitney Medical Library). The question needs to identify the patient or population we intend to study, the intervention or treatment we plan to use, the comparison of one intervention to another (if applicable) and the outcome we anticipate. These make up the four elements of the PICO model: Patient/ Problem, Intervention, Comparison and Outcome.
Sometimes PICO includes a "T" as a fifth component, which stands for time. Some versions of PICOT that include the T use this area to stand for type of study.