Adjusting for selection bias in retrospective, case-control studies
Open Access
- 14 May 2008
- journal article
- research article
- Published by Oxford University Press (OUP) in Biostatistics
- Vol. 10 (1), 17-31
- https://doi.org/10.1093/biostatistics/kxn010
Abstract
Retrospective case–control studies are more susceptible to selection bias than other epidemiologic studies as by design they require that both cases and controls are representative of the same population. However, as cases and control recruitment processes are often different, it is not always obvious that the necessary exchangeability conditions hold. Selection bias typically arises when the selection criteria are associated with the risk factor under investigation. We develop a method which produces bias-adjusted estimates for the odds ratio. Our method hinges on 2 conditions. The first is that a variable that separates the risk factor from the selection criteria can be identified. This is termed the “bias breaking” variable. The second condition is that data can be found such that a bias-corrected estimate of the distribution of the bias breaking variable can be obtained. We show by means of a set of examples that such bias breaking variables are not uncommon in epidemiologic settings. We demonstrate using simulations that the estimates of the odds ratios produced by our method are consistently closer to the true odds ratio than standard odds ratio estimates using logistic regression. Further, by applying it to a case–control study, we show that our method can help to determine whether selection bias is present and thus confirm the validity of study conclusions when no evidence of selection bias can be found.Keywords
This publication has 9 references indexed in Scilit:
- Inverse probability weighted estimation for general missing data problemsJournal of Econometrics, 2007
- Struggles with Survey Weighting and Regression ModelingStatistical Science, 2007
- Selection bias and its implications for case–control studies: a case study of magnetic field exposure and childhood leukaemiaInternational Journal of Epidemiology, 2005
- Hypospadias in Washington State: Maternal Risk Factors and Prevalence TrendsPediatrics, 2005
- A Structural Approach to Selection BiasEpidemiology, 2004
- Commentary: Berkson's Bias reviewedEuropean Journal of Epidemiology, 2002
- Do Confounding or Selection Factors of Residential Wiring Codes and Magnetic Fields Distort Findings of Electromagnetic Fields Studies?Epidemiology, 2000
- Imposing Moment Restrictions from Auxiliary Data by WeightingThe Review of Economics and Statistics, 1999
- Alternative Analytic Methods for Case-Control Studies of Estrogens and Endometrial CancerThe New England Journal of Medicine, 1978