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Evidence-Based Practice in Health

This guide includes a tutorial about Evidence-Based Practice (EBP) in Health, a Reference Shelf of supporting eBooks, and a Toolkit of online sources of evidence.

Types of Clinical Question

Recognising your clinical question's domain is an important part of the Evidence-Based Practice (EBP) process. Establishing the question type allows you to:

  • Identify the research methodology that provides the best evidence to answer the question.  Note that the hierarchy of evidence (covered in 1.3 Hierarchy of Evidence) will differ according to question type.
  • Select the best EBP Tools to search for the evidence. The Cochrane Database of Systematic Reviews, for example, only addresses treatment and prevention questions.  Other databases address questions of treatment and prevention, diagnosis, prognosis, etiology, quality improvement, and health economics, among others.
  • Select evidence filters in PubMed / CINAHL and other databases that will help narrow your search to papers using appropriate research methods.

Identifying your question type will also assist you in critically appraising the evidence based on the appropriateness and rigor of the research methods described in a paper.

Common Clinical Question Types

The table below explains the primary types of clinical questions and types of evidence to answer the question.1

Type or Domain Explanation Types of evidence to answer the question
Therapy (Treatment) Questions about the effectiveness of interventions in improving outcomes in sick patients / patients suffering from some condition.  These are the most frequently asked.  Among the many treatments offered by clinicians are medications, surgical procedures, excercise, and counseling about lifestyles changes. Randomised Controlled Trial (RCT)
Prevention Questions about the effectiveness of an intervention or exposure in preventing morbidity and mortality.  Similar to treatment questions. When assessing preventive measures, it is particularly important to evaluate potential harms as well as benefits. RCT or Prospective Study
Diagnosis Questions about the ability of a test or procedure to differentiate between those with and without a condition or disease. RCT or Cohort Study

Prognosis (Forecast)

Questions about the probable cause of a patient's disease or the likelihood that he or she will develop an illness. Cohort Study and/or Case-Control Series
Etiology (Causation) Questions about the harmful effect of an intervention or exposure on a patient.

Cohort Study
Meaning    Questions about patients' experiences and concerns.    Qualitative Study

Background Questions & Foreground Questions

Clinical questions can be categorised as either background or foreground.  Determining the type of question will help you to select the best resource to consult for your answer.

Background questions ask for general knowledge about a condition, test or treatment.  These types of questions typically ask who, what, where, when, how & why about things like a disorder, test, or treatment, or other aspect of healthcare.  For example:

What are the clinical manifestations of menopause?

What causes migraines?

Foreground questions ask for specific knowledge to inform clinical decisions. These questions typically concern a specific patient or particular population. They tend to be more specific and complex than background questions.  Quite often, foreground questions investigate comparisons, such as two drugs, or two treatments.   For example:

Is Crixivan effective in slowing the rate of functional impairment in a 45 year old male patient with Lou Gehrig's Disease?

In patients with osteoarthritis of the hip, is water therapy more effective than land-based exercise in restoring range-of-motion?


1. Fineout-Overholt, E. & Johnston, L. (2005), Teaching EBP: asking searchable, answerable clinical questions. Worldviews on Evidence-Based Nursing, 2, 157–160. doi: