st: error in -vanelteren- (1 group found, 2 required)

["Ariel Linden" <ariel.linden@gmail.com>]

Hi All,

I am getting an error when running the user-written program -valelteren-
(written by J. Coveney, downloaded from ssc).

The error message states that 1 group is found when 2 are required.  Clearly
there are 2 groups in the specified variable.

I emailed the author of code at two different email addresses but he's so
far non-responsive. 

Does anyone else experience this error? I am running Stata v 13.1

Ariel


****code****
.sysuse auto
. vanelteren price, by(foreign) strata( rep78 )
(1978 Automobile Data)

Generalized Wilcoxon-Mann-Whitney Ranksum Test (van Elteren's Test)


Variance of
Weighted Expected Weighted
Stratum | n | Ranksum | Ranksum | Ranksum
-------------+-------+-----------+----------+-------------
1 group found, 2 required
r(499);

. webuse cattaneo2
. vanelteren bweight, by(mbsmoke) strata(medu)
(Excerpt from Cattaneo (2010) Journal of Econometrics 155: 138-154)

Generalized Wilcoxon-Mann-Whitney Ranksum Test (van Elteren's Test)


Variance of
Weighted Expected Weighted
Stratum | n | Ranksum | Ranksum | Ranksum
-------------+-------+-----------+----------+-------------
0 | 42 | 18.08 | 15.5 | 0.660
1 group found, 2 required
r(499);
****end code****



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