Klaus777 发表于 2016-8-23 12:30 
variable id does not uniquely identify the observations
Your data are currently wide. You are ...
这是一个很简单的问题,报错已经很直白了,id should uniquely identify the observations。也就是每一年id对应的观测应该是唯一的,对原数据进行duplicates drop id, force,之后再reshape long var, i(id) j(year)应该就可以解决问题。