Variable	Test	Statistic	Degrees_of_Freedom	P_Value	Proportional_Hazards_Assumption
Risk Score (continuous)	Schoenfeld residuals (global)	2.228	1	0.136	Satisfied
Risk Group (binary high vs low)	Log-rank / stratified Cox	See Table 2 (main text)	1	<0.001 (significant stratification)	Applicable (binary grouping)