Nicola Tommasi
> >I believe there is a bug in the makematrix command.
> >
> >Evidence of bug :
> >
> >. summ d09a_rc d09b_rc d09c_rc d09d_rc score_9;
> >
> > Variable | Obs Mean Std. Dev.
> Min Max
> >-------------+---------------------------------------------
> -----------
> > d09a_rc | 1478 .7814614 .9512177
> -2 2
> > d09b_rc | 1442 .9036061 .9401232
> -2 2
> > d09c_rc | 1529 1.204709 .875393
> -2 2
> > d09d_rc | 1493 1.139317 1.007686
> -2 2
> > score_9 | 1584 1.000053 .7941874
> -2 2
> >
> >. makematrix tab9tot, from( r(N) r(mean) r(sd) r(min)
> r(max) ): su d09a_rc
> >d09b_rc d09c_rc d09d_rc score_9;
> >
> >tab9tot[5,5]
> > N mean sd min max
> >d09a_rc 1351 .78756477 .94986591 -2 2
> >d09b_rc 1351 .92376018 .94168773 -2 2
> >d09c_rc 1351 1.2398224 .85734195 -2 2
> >d09d_rc 1351 1.1591414 .9980665 -2 2
> >score_9 1351 1.0275722 .77329762 -2 2
> >
-makematrix- is a user-written command available
on SSC.
I see no bug here; the issue is documented in the
help for the command and in any case is fairly clear from
the output.
-summarize-, given several variables, cycles through
those variables one by one and uses as many observations
as it can, namely all those observations specified
for which non-missing values are available for
_each_ variable.
In Nicola's data, there are lots of missing
values and the pattern of missing values is not
the same for each variable.
-makematrix- uses the opposite default, namely
that it uses the observations specified for
which _all_ variables specified are non-missing.
The rationale for this is to ensure consistency
of results, so that for example a correlation "matrix"
so produced really is a correlation matrix worthy
of the name, with the correct eigenproperties etc.
Nicola wants the -listwise- option:
-listwise- specifies that the results of cmd should be
determined for as many observations as possible.
Note that as a consequence the number of observations used
in each calculation may differ. By default casewise deletion
is used to ensure consistency in observations selected.
. makematrix tab9tot, from( r(N) r(mean) r(sd) r(min) r(max) ),
listwise: su d09a_rc d09b_rc d09c_rc d09d_rc score_9
Nick
[email protected]
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