Table 4.

Discrimination measures and hazard ratios evaluated in the derivation and validation datasets

Measure	Derivation data		Validation data
	Estimate	SE	Estimate	SE
Harrell c-index	0.673	0.009	0.658	0.016
Gönen & Heller K	0.655	0.008	0.645	0.015
Explained variation ($R_D^2$)	0.166	0.017	0.145	0.033
HR: group 2 versus 1	1.58	0.19	1.63	0.35
HR: group 3 versus 1	3.33	0.39	3.34	0.70
HR: group 4 versus 1	4.75	0.60	6.33	1.54

All values are based on the PI of the prognostic model. Risk groups were defined as described in the text. Standard errors (SE) for the c-index and for RD2 were estimated from 200 bootstrap samples. HR = hazard ratio.