Example of Differential Misclassification Bias

Pregnancy and Congenital Malformations

Lead Author(s): Jeff Martin, MD

Differential Misclassification of Exposure Variables

One of the classic examples of differential misclassification of exposure are studies of exposures during pregnancy and congenital malformations.

Schematic of Differential Misclassification


Differential Sensitivity and Specificity of Exposure Measurement

In these studies first, we may have differential recall of various exposures during pregnancy, Second, we may have differential specificity.

Result: Overestimation

The result of all of this is that there is overestimation of the association between the exposure and the outcome.