出现错误
set trace on

. xtbalance,range(2010 2011)
------------------------------------------------------------ begin xtbalance ---
- version 8.0
- syntax , Range(numlist min=2 max=2 int ascending) [Miss(varlist) Generate(newv
> arname)]
invalid syntax
-------------------------------------------------------------- end xtbalance ---
r(197);
然后我就 ssc install xtbalance, replace
更新到2.01版本
结果还是同样错误。

. xtdes

id:2, 4, ..., 601999 n = 1533
year:2010, 2011, ..., 2011 T = 2
Delta(year) = 1 unit
Span(year)= 2 periods
(id*year uniquely identifies each observation)

Distribution of T_i: min 5% 25% 50% 75% 95% max
1 2 2 2 2 2 2

Freq.Percent Cum. |Pattern
---------------------------+---------
1526 99.54 99.54 |11
4 0.26 99.80 |1.
3 0.20100.00 |.1
---------------------------+---------
1533 100.00 |XX