momingqimiao7 发表于 2018-8-22 09:50
看你估计窗口期是不是只选了30个交易日h
by stkcd: gen event_window=1 if dif>=-5 & dif<=5
egen count_event_obs=count(event_window), by(stkcd)
by stkcd: gen estimation_window=1 if dif<-30 &dif>=-60
egen count_est_obs=count(estimation_window), by(stkcd)
replace event_window=0 if event_window==.
replace estimation_window=0 if estimation_window==.
tab stkcd if count_event_obs<5
tab stkcd if count_est_obs<30
drop if count_event_obs<5
drop if count_est_obs<30
是不是这个啊,不过倒是都能算出来predicted_return, 是不是也不影响这个结果的计算