Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies

Figure 1

(a) Stratified random selection process of a two-phase case-control study. Feature characteristics known about a whole finite population are typically features which are inexpensive to measure and called characteristics recorded in Phase 1. The expensive characteristics are recorded only in Phase 2—in the final sample

(b) Exemplary cross table for data before (left) and after (right) the selection process of a two-phase case-control study. There is a clear dependency between exposure and disease in the population. After the sampling process, this dependency vanishes completely for the final sample