不知道是哪里出了问题，平行趋势检验出来这么个诡异图cd"C:\Users\young\Desktop\毕业论文\数据"
import excel using Postyear.xlsx,first clear
tabulate post


cd"C:\Users\young\Desktop\毕业论文\数据"
import excel using STATA-two.xlsx,first clear
//打开文件
gen c=0
replace c=1 if gender=="男"
destring code,replace
encode industry,gen(ind)
format code %06.0f
//str-num的格式修改
rename c gender1
*设定面板，生成时间标识
xtset code year

summarize post age gender1 roa roe tobinq power firmage size lev dual edugap
//描述性统计

gen time=(year>=post)
//生成实验期变量，post后赋值为1，否则为0
gen treat=(relation==1)
//生成实验期变量，relation为1的赋值1，否则0
gen did=time*treat
//生成虚拟变量

*平行趋势检验,事件研究法
gen period = year - post
tab period

//生成代际传承前后期数

//生成年份虚拟变量与实验组虚拟变量的交互项
forvalues i = 5(-1)1{
gen pre_`i' = (period == -`i' & treat == 1)
}

gen current = (period == 0 & treat == 1)

forvalues j = 1(1)5{
gen  post_`j' = (period == `j'& treat == 1)
}

drop pre_1
//将代际传承前第一期作为基准组
xtreg roa pre_* current post_* power firmage size lev dual i.year,fe

coefplot, baselevels ///
keep(pre* current post*) ///
vertical ///转置图形
coeflabels(pre_5=-5 pre_4=-4 pre_3=-3 pre_2=-2 pre_1=-1 ///
current=0 post_1=1 post_2=2 post_3=3 post_4=4 post_5=5) ///
yline(0,lwidth(vthin) lpattern(solid) lcolor(teal)) ///
xline(5,lwidth(vthin) lpattern(solid) lcolor(teal)) ///
ylabel(-1(0.5)4,labsize(*0.85) angle(0)) xlabel(,labsize(*0.85)) ///
ytitle("Coefficients") ///
msymbol(O) msize(small) mcolor(gs1) ///plot样式
addplot(line @b @at,lcolor(gs1) lwidth(medthick)) ///增加点之间的连线
ciopts(recast(rline) lwidth(thin) lpattern(dash) lcolor(gs2)) ///置信区间样式
graphregion(color(white)) //白底