黃河泉 发表于 2016-8-5 09:43 
既然没有重复值,哪到底要解决什么问题?
. gen lag_GINVT = L.GINVT
not sorted
r(5);
. xtset id year
repeated time values within panel
r(451);
. duplicates report
Duplicates in terms of all variables
--------------------------------------
copies | observations surplus
----------+---------------------------
1 | 965 0
--------------------------------------
. duplicates list
Duplicates in terms of all variables
(0 observations are duplicates)
.