Determination of risk factor associations with questionnaire outcomes: a methods case study.
Increasingly in biomedical studies, health status is inferred through a series of questionnaire item responses. Challenges for analyzing associations between such responses and risk factors include multiplicity-many indicators must be combined to derive summary statements about health status, and measurement error-persons' self-report fluctuates due to causes other than substantive health changes. In order to deal with these challenges, the authors propose a strategy which comprises three methods: 1) score the item responses, then regress the score on predictors; 2) regress each item response on predictors, accounting for within-person associations; and 3) summarize and analyze the item responses jointly, using a latent variable model. The authors develop modeling and diagnostic procedures for method 3. They then show how the three-method analytic strategy can be used to solve the problem of determining which aspects of vision are associated with self-reported functioning in activities that require seeing at a distance. They demonstrate that methods 2 and 3 illuminate basic findings from method 1 by adding specificity, describing patterns as well as severities of health impairments, and identifying isolated items that relate to risk factors differentially than others. They conclude that the three-method strategy specifies how risk factors determine questionnaire-based health outcomes substantially better than any of the methods in isolation.
Bandeen-Roche
K
K
Department of Biostatistics, School of Hygiene and Public Health, The Johns Hopkins University, Baltimore, MD 21205, USA.
Huang
G H
GH
Munoz
B
B
Rubin
G S
GS
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008297:Male; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care; D012044:Regression Analysis; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014785:Vision, Ocular; D014792:Visual Acuity