Table 5.

Assignment method of independent variable.

Independent variable	Assignment method
Educational level	Primary school or below = 1; Middle school = 2;
	vocational school = 3; diploma school or above = 4
Previous employment	Unemployed = 0,0; Non-medical = 1,0; Medical = 0,1
Work experience(year)	<0.3 = 1; 0.3–1.0 = 2; 1.1–3.0 = 3; 3.1–5.0 = 4; >5.0 = 5
Employment method	Temporary = 0,Permanent = 1
Qualification situation	No = 0,Yes = 1
Monthly salary(CNY)	1500–2500 = 1; 2501–3500 = 2; 3501–4500 = 3;
	4501–5500 = 4; ≥5501 = 5
Perceived health status	Poor = 1,General = 2,Good = 3,Excellent = 4
Training times within 1 year year	None = 1,1–6 times = 2,7–11 times = 3,12 times or above = 4