Table 1.

Composition of bias subgroups in train/validation/test splits of the dataset.

	Morphology + Intensity subgroup	Morphology + No Intensity subgroup	No Morphology + Intensity subgroup	No Morphology + No Intensity subgroup
Disease class	418/206/210	306/149/151	298/151/146	56/30/23
Non-disease class	55/30/26	300/149/153	303/146/153	420/212/212

Columns indicate subgroup with given bias effects (e.g., Morphology + Intensity = images with both morphology and intensity bias effects, Morphology + No Intensity = images with morphology bias effect but not intensity bias effect).