Based on a thesis accepted for the degree of Doctor of Philosophy at the University of the Witwatersrand.
Exposure—response relationship for a dichotomized response when the continuous underlying variable is not measured†
Article first published online: 12 OCT 2006
Copyright © 1988 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 7, Issue 9, pages 955–964, September 1988
How to Cite
Irwig, L. M. and Groeneveld, H. T. (1988), Exposure—response relationship for a dichotomized response when the continuous underlying variable is not measured. Statist. Med., 7: 955–964. doi: 10.1002/sim.4780070907
- Issue published online: 12 OCT 2006
- Article first published online: 12 OCT 2006
- Manuscript Revised: DEC 1987
- Manuscript Received: OCT 1986
- Epidemiological methods;
- Dose—response relationships;
- Diagnostic errors
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.