CORRECTING FOR MEASUREMENT ERROR IN AN EXPOSURE-RESPONSE RELATIONSHIP BASED ON DICHOTOMISING A CONTINUOUS DEPENDENT VARIABLE |
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Authors: | Les M. Irwig Hennie T. Groeneveld Judy M. Simpson |
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Affiliation: | Institute for Biostatistics of the South African Medical Research Council and University of Sydney;Inst. for Biostatistics of the South African Medical Research Council, Johannesburg, South Africa;Department of Statistics, University of Pretoria, South Africa |
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Abstract: | Random error in a continuous outcome variable does not affect its regression on a predictor. However, when a continuous outcome variable is dichotomised, random measurement error results in a flatter exposure-response relationship with a higher intercept. Although this consequence is similar to the effect of misclassification in a binary outcome variable, it cannot be corrected using techniques appropriate for binary data. Conditional distributions of the measurements of the continuous outcome variable can be corrected if the reliability coefficient of the measurements can be estimated. An unbiased estimate of the exposure-response relationship is then easily calculated. This procedure is demonstrated using data on the relationship between smoking and the development of airway obstruction. |
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Keywords: | Epidemiological methods dose-response relationships diagnostic errors |
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