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Exposure—response relationship for a dichotomized response when the continuous underlying variable is not measured
Author(s) -
Irwig L. M.,
Groeneveld H. T.
Publication year - 1988
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780070907
Subject(s) - statistics , mathematics , polychoric correlation , correlation , observational error , observer (physics) , variable (mathematics) , reliability (semiconductor) , econometrics , mathematical analysis , physics , geometry , quantum mechanics , power (physics)
Radiological assessment of pneumoconiosis is an example of a dichotomized variable, namely one that is analysed as a binary response but in fact has an underlying continuum, which in this case is not measurable. Estimates of exposure—response relationships vary greatly for different observers of a dichotomized response variable because of random error of measurement and differences in the threshold implicitly chosen by each observer for categorizing cases. We present a method of using the biserial correlation coefficient and normal distribution theory to estimate exposure—response relationships at any required threshold for each observer. Exposure—response relationships can also be corrected for random observational error using the reliability coefficient, calculated as the tetrachoric correlation between repeat observations by readers.