# Re: st: AW: help interpreting SVY output

 From "Tomeka Davis" To Subject Re: st: AW: help interpreting SVY output Date Tue, 10 Nov 2009 10:24:02 -0500

```Sorry for the  lack of clarity.  After svyset I use the svy: regress
command.  This is where I get a count of the strata and PSUs, as in the
following set of results.

. svy:  regress math  perelm bymach lunch whtpct  member suburban
townrur  midwest west south pupilexp
(running regress on estimation sample)

Survey: Linear regression

Number of strata   =        87                  Number of obs      =
7741
Number of PSUs     =       455                 Population size    =
2079494.4
Design
df          =       368
F(  11,
358)    =      4.48
Prob > F
=    0.0000

R-squared          =    0.0318

------------------------------------------------------------------------------
|                 Linearized
math     |      Coef.   Std. Err.      t    P>|t|     [95% Conf.
Interval]
-------------+----------------------------------------------------------------
perelm   |  -.0027674    .009638    -0.29   0.774    -.0217199
.0161851
bymach |   .0012292   .0014766     0.83   0.406    -.0016743
.0041328
lunch |   .1672079   .0848558     1.97   0.050     .0003447
.3340711
whtpct |  -.0002636   .0007161    -0.37   0.713    -.0016717
.0011444
member |   .0000399   .0000801     0.50   0.619    -.0001177
.0001974
suburban |  -.0351555   .0394778    -0.89   0.374    -.1127859
.0424749
townrur |  -.0969806    .048962    -1.98   0.048    -.1932611
-.0007001
midwest |   -.062071   .0501236    -1.24   0.216    -.1606357
.0364937
west |   .0914772   .0535214     1.71   0.088    -.0137689
.1967233
south |   .0783868   .0576097     1.36   0.174    -.0348986
.1916722
pupilexp |   8.25e-07   6.31e-06     0.13   0.896    -.0000116
.0000132
_cons |   2.259222   .1675219    13.49   0.000     1.929801
2.588642
------------------------------------------------------------------------------
Note: strata with single sampling unit treated as certainty units.

Thanks.

>>> "Martin Weiss" <martin.weiss1@gmx.de> 11/10/2009 7:38 AM >>>

<>

Which "standard errors" are you referring to? -svyset- only declares
the
design to Stata.

HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Tomeka
Davis
Gesendet: Montag, 9. November 2009 22:33
An: statalist@hsphsun2.harvard.edu
Betreff: st: help interpreting SVY output

Hello -

This is my first time using the set of SVY commands in Stata and I have
a
few questions.  When I use the syntax:

svyset psu [pweight=pw], strata (strata)

Stata 1) does not calculate the standard errors and 2) I  get a
message
stating that standard errors are" missing because of stratum with
single
sampling units".

Furthermore, I am also getting incorrect counts for my PSU.  There
were
originally only 100 PSUs in my data.  However, I do get standard errors
with
the following syntax:

svyset psu [pweight=pw], strata (strata) || _n, singleunit(certainty)

But I still get a 455 PSU count.  Again, I have never used SVY to
account
for clustering and complex survey design. I would appreciate any

Thank you.

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```