Asking Answerable Questions

A question can be broken down into five components

• Population – Consider this in terms of the people the condition or disease of interest and the setting
• Intervention/Exposure – Consider the frequency intensity or dose of the intervention or exposure
• Comparison – This is your control group this is often normal care or a placebo in the care of a drug trial
• Outcome – Think or both direct outcomes such as hip fracture or MI or surrogate outcomes for example bone density or raised blood pressure if the time frame is not long enough to see the direct outcome. 
• Time – This is the relevant time frame, give enough time for the outcome to occur

Here are some examples

Example One

Population – Men with CVD risk factors in the community setting

Intervention – Low dose aspirin

Comparison – No aspirin

Outcome – reduced incidence of MI

Time – a five year period

The question becomes

In men with cardiovascular disease risk factors does low dose aspirin compared with no aspirin reduced the incidence of MI over a five year period?

Example 2

Population – People over 65 years old who are malnourished living in residential care

Intervention – Oral supplements

Comparison – no supplements

Outcome – improved nutrition status and weight gain

Time – six months

The question

In people over sixty five who have malnutrition and are living in residential care, do oral supplements compared with no oral supplements improve nutritional status and lead to weight gain over a six month period?

Related Web Links

• Adjusting for baseline risk: Number needed to treat
• Asking Focused Clinical Questions (Centre of Evidence Based Medicine)
• Benefits of best practice guidelines: evaluating and applying the evidence – October 2003 (PDF)
• Tutorial on Evidence Based Medicine
• CONSORT - Checklist  Items to include when reporting a randomized trial
• Estimating CVD risk and treatment benefit
• Glossary of Terms
• PICO tool from PubMed
• Risk Calculating