variables interpretation Obs Mean Standard deviation Min Max Wage Total wage income in 2014 3208 10.124 0.915 4.787 12.92 Work never = 1, once several months = 2, once a month = 3, twice or three times a month = 4, once or twice a week = 5, three to four times a week = 6, almost every day = 7, Work = 1 if frequencies ≥ 6, otherwise Work = 0 3208 0.437 0.496 0 1 Urban Dummy variable (urban = 1, rural = 0) 3208 0.694 0.461 0 1 Male Dummy variable (male = 1, female = 0) 3208 0.568 0.495 0 1 Age range from 16 to 65 3208 32.367 9.564 16 62 Agesq/100 Square of age divided by 100 3208 11.390 6.862 2.56 38.44 Married Dummy variable (being married = 1，else = 0) 3208 0.718 0.450 0 1 Illiterate/semi-literate Illiterate/semi-literate 3208 0.015 0.123 0 1 Primary school Primary school 3208 0.111 0.315 0 1 Junior high school Junior high school 3208 0.290 0.454 0 1 High school/secondary school/technical school/vocational high school High school/secondary school/technical school/vocational high school 3208 0.276 0.447 0 1 College College 3208 0.177 0.382 0 1 Undergraduate Undergraduate 3208 0.130 0.337 0 1 Health Dummy variable（healthy = 1, else = 0) 3208 0.869 0.337 0 1 Otherwork Numbers of other work except for the main job 3208 0.137 0.443 0 4 Promotion Whether got promoted in the job, dummy variable (promoted = 1, else = 0) 3208 0.119 0.324 0 1 Computer Whether a computer needs to be used in the work, dummy variable (yes = 1, else = 0) 3208 0.589 0.492 0 1 Scale Number of employees 3208 4.250 1.901 0 1 Cash Whether there is Cash benefits in the job, dummy variable (yes = 1，else = 0) 3208 0.407 0.491 0 1 Welfare Whether there is Welfare benefits in the job, dummy variable (yes = 1，else = 0) 3208 0.446 0.497 0 1 Intelligence The level of intelligence 3208 0.928 0.259 0 1 Contra Signing a contract or not, dummy variable (contra = 1 if signing a contract, contra = 0 else) 3208 0.569 0.495 0 1 East East region 3208 0.426 0.495 0 1 Centre Central region 3208 0.247 0.431 0 1 West West region 3208 0.177 0.382 0 1 Northeast Northeast region 3208 0.150 0.357 0 1 Lpgdp GDP per person in the local 3208 10.828 0.415 10.181 11.549 Employer Dummy variables of employer 3208 3.504 1.184 1 8 Occupation Dummy variables of occupation 3208 8.384 5.561 1 19