tsset fd yr
       panel variable:  fd (unbalanced)
        time variable:  yr, 1998 to 2007, but with gaps
                delta:  1 unit
. levpet lny ,free(lnl) proxy(lnm) capital(lnk) revenue
tsset fn2 yr
       panel variable:  fn2 (unbalanced)
        time variable:  yr, 1998 to 2007, but with gaps
                delta:  1 unit
. levpet lny ,free(lnl) proxy(lnm) capital(lnk) revenue
repeated time values within panel
r(451);
为什么用tsset 后没有显示 repeated time values within panel, 而用levpet命令则显示有repeated time values within panel,并且用duplicates drop fd yr ,force，结果显示没有观测值删除，即并没有重复值， 因而本人对此十分困惑,麻烦各位高手帮帮忙，本人万分感激!!!