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Questionnaires and Interviews. Steven R. Cummings, MD Director, S.F. Coordinating Center. Where we left my story…. Resveratrol increases speed, endurance & strength & lifespan My hypothesis: Those who consume resveratrol have longer healthy life
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Questionnaires and Interviews Steven R. Cummings, MD Director, S.F. Coordinating Center
Where we left my story… • Resveratrol increases speed, endurance & strength & lifespan • My hypothesis: Those who consume resveratrol have longer healthy life • A randomized trial for mortality was too big and NIA didn’t fund my small trial of resveratrol and gait speed • So…
An opportunity to piggy back • A Coordinating Center cohort study about aging is planning a new visit • I could add questions about intake of resveratrol • I could test subsequent mortality or cross-sectional associations with health
An opportunity to piggy back • A SFCC study about aging is planning a new visit • Men ≥ age 75 years old • I could add questions about intake of resveratrol • I could test subsequent mortality or cross-sectional associations with health • …cheaply • But additions must be short
Measurements I need to test my hypothesis • “Resveratrol intake” • “Healthy” • “Lower mortality” • But insufficient number of men taking resveratrol and too few deaths to test whether resveratrol is associated with mortality
Measurements I need to test my revised hypothesis • “Resveratrol intake” • “Health”
1st steps • Are there standard questionnaires? • Must I make my own?
Where to find questionnaires • Experts and articles in the area of research • Search the web • e.g. QualityMetrics: www.qualitymetric.com • General health status (SF36) • A few disease-specific measurements • Must get a license • SF Coordinating Center
Resveratrol intake comes mainly from red wine and supplements • I need to quantify the average amount of resveratrol the participant takes • I could add questions about use of resveratrol supplements • I could add questions about wine intake
The Coordinating Center has a standard questionnaire on alcohol use • Have you drunk at least 12 ‘drinks’ of alcohol in past 12 months & average drinks per week. • Easily modified to substitute ‘red wine’ for ‘alcohol’
The Coordinating Center has a standard questionnaire on medication use • Do you currently take ____? __ No (skip to X) __ Yes • How often? • __ daily __ weekly __ less often • What dose? ___
I must adapt the questionnaire to measure resveratrol intake • Do you currently take ____? __ No (skip to X) __ Yes • How often? • __ daily __ weekly __ less often • What dose? ___
Quantifying resveratrol intake from supplements • Do you currently take tablets or capsules containing resveratrol? • Yes No (skip to X) • How often? • __ daily __ weekly __ less often • What dose? _____
Quantifying resveratrol intake from supplements • Do you currently take tablets or capsules containing resveratrol? • Yes No (skip to X) • How often? • __ daily __ weekly __ less often • What dose? _____ What’s wrong with this question?
Quantifying resveratrol intake from supplements “Or” can be confusing • Do you currently take tablets or capsules containing resveratrol? • Yes No (skip to X) • How often? • __ daily __ weekly __ less often • What dose? _____ It is also sold as a liquid Some are not called ‘resveratrol’ May not know; not on label These problems might be discovered by pretesting with people who take resveratrol
Clarified the question…but • Do you currently take supplements containing resveratrol? • Yes No (skip to X) • How often? • __ daily __ weekly __ less often • What dose? _____ Some are not called ‘resveratrol’ May not know; not on label Only few brands are absorbed
Must be done by interview • Please bring all of the medications or supplements that you have taken in the past month • Frequency of use • __ daily __ weekly __ less often • Dose __ __ __ mg • Brand _________ Open ended Must be coded with a dictionary
“Health” • MrOS uses the SF-12 to assess health status • It is extensively validated • For example, large differences between patients with and without chronic disease • Changes in response to interventions, such as exercise or medical treatments
‘Standard’ or ‘validated’ instruments • Usually the best choice • Probably free(er) of bugs • Looks better in papers and grants • However, • May not measure what you want • May not apply to your population • May be longer than you need
Questions in the SF-12(for patients > 70-95) Some men >75 might not do these This might be discovered by pretesting men >75
The ‘validated’ SF-12 • A good choice because • Extensively tested, few/no bugs • Would look better in papers and grants • However, • Does not measure ‘health’ related to speed, strength, endurance • Many questions about mood and pain • May not apply to men > age 75 years
What do I want to measure? • Walking speed • Already to be measured in MrOs • General health question • Physical quality of life • Just the ‘physical’ components of SF-12
Pretest, pretest, pretest • Start with a few friends or colleagues • Try it on 2 or 3 like subjects in your study • Men over age 75; extremes (age, education…) • Discuss the answers with the volunteers • Revise and retest • Test the ‘final’ in more and diverse subjects • Potential goals: clarity, time, frequency of answers • Bigger efforts: test reliability and validity
Administering Questions • Questionnaires are more efficient than interviews • If needed, follow-up review of questions • Sometimes, interviews are the only way • Use electronic methods as much as possible • Online tools (mix of free & pay service) • www.surveymonkey.com • www.zoomerang.com • 11 reviewed at www.techsoup.org/learningcenter/software (search “online survey tools”)
Summary • Carefully define what you want to measure • Search for ‘standard’ instruments • Do they measure what you want? • If you make your own: avoid pitfalls • Clarity; avoid “and,” “or” • Pretest, pretest, pretest…