Table 1.

Criteria for model quality estimation.

Group	Items
High-quality group	EPV ≥10 AND
	Variable in final model <10 AND AUC/c-index estimated for both training and external or internal validation sets
Medium-quality group	EPV ≥10 AND
	Presence of external or internal validation set but only training set is estimated by receiver operating characteristic curve/c-index
Low-quality group	No performance estimation OR
	No internal and external validation set OR EPV <10

EPV, event per variable.