假设变量安排如下:
id year month y x1 x2 x3
则处理命令如下:
*-月份重新编码 1,2,3 ……
gen res = .
egen m123 = group(year month) , label lname(year_month)
sum m123
global N = r(max)
*-分年度、月份回归分析
cap drop res
cap drop e
gen res = .
forvalues i = 1/$N{
qui reg y x1 x2 x3 if (m123==`i')
qui predict e if e(sample), res
qui replace res = e if e(sample)
drop e
}