样本数据截图（企业数据）：

<code>use data.dta, clear

* 控制控制变量 ControlVariables

global ControlVariables SIZE ROA LEV ATTR TOP1 ACADEMIC MARKET i.IND i.year

* 链式中介命令

capture program drop mediation

program mediation, rclass

  gsem (med1 <- x $ControlVariables) (med2 <- x $ControlVariables) (y <- med2 med1 x $ControlVariables), vce(cluster stkcd) nocaps 

  return scalar cie1 = _b[med1:x]*_b[y:med1]

  return scalar cie2 = _b[med2:x]*_b[y:med2]

  return scalar direct_effect=_b[y:x]              

  return scalar total_effect=_b[y:x]+_b[med1:x]*_b[y:med1]+_b[med2:x]*_b[y:med2]

  end

set seed 12345

* 运行命令

<code>mediation

*Bootstrap 中介效应

<code>bootstrap r(direct_effect) r(cie1) r(cie2)  r(total_effect), reps(20) : mediation

estat boot, bc percentile