TABLE 3.

Assignment of independent variables.

Independent variable	Coding
Educational level	Junior high school or below (Z1 = 0, Z2 = 0, Z3 = 0); Senior high school/technical secondary school (Z1 = 1, Z2 = 0, Z3 = 0); Junior college (Z1 = 0, Z2 = 1, Z3 = 0); Bachelor’s degree or above (Z1 = 0, Z2 = 0, Z3 = 1)
Average monthly household income per capita (RMB)	<3000 (Z1 = 0, Z2 = 0), 3000 ∼ 6000 = (Z1 = 1, Z2 = 0), >6000 = (Z1 = 0, Z2 = 1)
Surrogate decision-maker age	Continuous variable
Decision preparedness (standardized score)	Continuous variable
Shared decision-making (total score)	Continuous variable