Table 2 | Health Information Research Unit

Purpose Category	Definition
Causation (Etiology)	Content pertains directly to determining if there is an association between an exposure and a disease or condition. The question is “What causes people to get a disease or condition?”
Prognosis	Content pertains directly to the prediction of the clinical course or the natural history of a disease or condition with the disease or condition existing at the beginning of the study.
Diagnosis	Content pertains directly to using a tool to arrive at a diagnosis of a disease or condition.
Therapy	Content pertains directly to an intervention for therapy (including adverse effects studies), prevention, rehabilitation, quality improvement, or continuing medical education.
Costs	Content pertains directly to the costs or financing or economics of a health care issue.
Economics	Content pertains directly to the economics of a health care issue (subset of cost articles).
Clinical Prediction Guide	Content pertains directly to the prediction of some aspect of a disease or condition.
Qualitative	Content relates to how people feel or experience certain situations, and data collection methods and analyses are appropriate for qualitative data.
Something else	Content of the study does not fit any of the above definitions.