/ Extra-large Cities / Gas supply industry / Gdp Growth Rate / Home Town / household registration system / hukou system / Imputed income / income inequality China / Industrial Injury Insurance / Job Referral System / Labour / income economics / Labour Economics / Learning Supervision / left-behind children / Medium sized cities / Migrant workers / Panel Data / propensity score / Regional Economic Convergence / Relative Income / Rural Labor Force / Rural Migrant Workers / rural-urban migration / self-rated health / Self-rated Health Status / Significant Negative Impact / social network analysis