TABLE 2

Definition of Study Purpose

Study PurposeDefinition
TherapyaDetermine the effect of different treatments on improving patient function or avoiding adverse events
DiagnosisaEstablish the power of an intervention to differentiate between those with and without the disease
Show disease manifestations
Show causes of signs and symptoms (differential diagnosis)
PrognosisaEstimate the future course of disease
Identify factors that modify prognosis
HarmaAscertain the effects of potentially harmful agents (including therapies) on patient function, morbidity rates, and mortality rate
Epidemiological investigationShow the prevalence or incidence of a disease or risk factor
Show associations between risk factors and diseases
Health servicesInvestigate issues of cost and quality in the delivery of health care
Study health care providers and systems
Study health service research itself
  • a Adapted from Users’ Guide to the Medical Literature: Essentials of Evidence-Based Clinical Practice.13