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Re: st: corr_svy & covariance matrix for survey data
As the help file indicates, the -print()- option suppresses printing of
correlations with p< the value you specify:
print(#) specifies the significance level of correlation coefficients to
be printed. Coefficients with larger significance levels are left
blank. print(10) would list only coefficients significant at the 10%
level or better.
- Nick Winter
Ishtar Govia wrote:
Thanks Nick. The correlation runs successfully with my data, except for
one issue, the values for one combination of variables (thkdish by
trethara) are missing. Any ideas what might have caused this hole in the
matrix?
. corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor [pweight=wgtcent], strata(stratum)
psu(clust) subpop(dgs1sp) obs sig print(10)
Survey Correlation
pweight: wgtcent
Strata: stratum
PSU: clust
Number of observations: 674
| lesscurt lessresp poorserv notsmart
actfraid thkdisho actbettr callnmes trethara follstor
-------------+------------------------------------------------------------------------------------------------------------------------
lesscurt | 1.0000
| 674
|
|
lessresp | 0.8360 1.0000
| 674 674
| 0.0000
|
poorserv | 0.4326 0.4556 1.0000
| 674 674 674
| 0.0003 0.0002
|
notsmart | 0.5480 0.6199 0.4787 1.0000
| 674 674
674 674
| 0.0000 0.0000 0.0000
|
actfraid | 0.4981 0.5632 0.4310 0.5037 1.0000
| 674 674
674 674 674
| 0.0000 0.0000 0.0001 0.0000
|
thkdisho | 0.4426 0.4273 0.4048 0.5294
0.4423 1.0000
| 674 674
674 674 674 674
| 0.0001 0.0010 0.0001
0.0011 0.0182
|
actbettr | 0.5747 0.6057 0.3899 0.6373
0.6112 0.4671 1.0000
| 674 674
674 674 674 674 674
| 0.0000 0.0000 0.0030 0.0000
0.0000 0.0010
|
callnmes | 0.3420 0.3819 0.3722 0.5454
0.3377 0.3830 0.4690 1.0000
| 674 674
674 674 674 674 674
674
| 0.0027 0.0015 0.0000
0.0001 0.0053 0.0243 0.0026
|
trethara | 0.2388 0.3227 0.3974 0.4355
0.4107 0.4221 0.7472 1.0000
| 674 674
674 674 674
674 674 674
| 0.0093 0.0050 0.0001 0.0175
0.0130 0.0112 0.0001
|
follstor | 0.3973 0.4183 0.5286 0.4711
0.4799 0.3877 0.4689 0.4855 0.5464 1.0000
| 674 674 674
674 674 674 674 674
674 674
| 0.0000 0.0000 0.0001 0.0031
0.0000 0.0014 0.0005 0.0029 0.0005
--------------------------------------------------------------------------------------------------------------------------------------
Key: Estimated Correlation
Number of observations
Significance Level
Ishtar Govia
[email protected]
On Oct 3, 2008, at 8:32 AM, Nick Winter wrote:
Hi,
-lw- is not an option because listwise is the default. So simply do
not specify -pw-, and you will get listwise deletion.
-NW
Ishtar Govia wrote:
Thanks, Nick. The background information on the command and the Stata
versions was insightful. The recommendations re: getting around the
limitations of the syntax for the subpop were very helpful. I created
the single variable (cases either in or out of the subpop) and the
following code ran successfully.
corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor [pweight=wgtcent],
strata(stratum) psu(clust) subpop(dgs1sp) pw obs sig print(10)
I tried to rerun it specifying a listwise correlation but received
the following error message:
corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor [pweight =wgtcent],
strata(stratum) psu(clust) subpop(dgs1sp) lw obs sig print(10)
option lw not allowed
r(198);
Is there a reason that lw option for -corr_svy- is not allowed? Or is
this again something that is specific to the command being a version
7 command? Or is there some other command that is used to generate
the listwise correlation using the -corr_svy-?
On Oct 2, 2008, at 1:02 PM, Nick Winter wrote:
Hi,
I wrote -corr_svy-, so here goes.
There are a couple of things going on here: (1) -corr_svy- is a
version 7 command, and seems to be having some trouble interacting
with the way that Stata 10 stores the survey characteristics as set
by -svyset-. (2) -corr_svy- uses the older, more limited syntax for
the -subpop()- option.
Issue (2) means that your subpop option must be specified as a
single variable name that takes on values 1 or 0 for cases that are
in or out of your subpopulation, respectively. If you have a
complex condition, you must first generate such a variable.
So, the following *should* work, but does not:
. sysuse auto
. svyset rep78 [pw=weight]
. corr_svy mpg price , subpop(foreign) sig
Survey Correlation
pweight: <none>
Strata: <one>
PSU: <observations>
Number of observations: 22
| mpg price
-------------+------------------------
mpg | 1.0000
|
|
price | -0.6313 1.0000
| 0.0042
--------------------------------------
Key: Estimated Correlation
Significance Level
As indicated in the output, -corr_svy- has ignored the survey
characteristics.
However, you can specify the survey characteristics in the
-corr_svy- command itself:
. corr_svy mpg price [pw=weight], psu(rep78) subpop(foreign) sig
Survey Correlation
pweight: weight
Strata: <one>
PSU: rep78
Number of observations: 21
| mpg price
-------------+------------------------
mpg | 1.0000
|
|
price | -0.5735 1.0000
| 0.0344
--------------------------------------
Key: Estimated Correlation
Significance Level
This gives you what you wanted.
(-corr_svy- will also set the survey characteristics you specify in
a way that subsequent calls to -corr_svy- can see, so you really
only need to specify them in the first run.)
What's going on? With version 9 Stata reworked completely the way
that survey characteristics are stored, presumably to support the
enhancements to the survey capabilities (such as supporting multiple
rounds of sampling). -corr_svy- uses the un/non-documented Stata
program -svy_get- to retrieve survey characteristics if they are not
specified in the command line. Unfortunately this is a Stata 8
command, and cannot "see" the version 9+ survey characteristics.
In the long run I will fix -corr_svy- to deal with the new survey
characteristics. In the short run you can simply specify them when
you run -corr_svy_, or with a call to the version 8 -svyset-, like
this:
. version 8: svyset ....
As a side effect, this means that -corr_svy- cannot deal with the
more complex sample specifications allowed with version 9+.
- Nick Winter
Ishtar Govia wrote:
Dear List,
I am using Stata 10/SE 10.1 for Macs. I have two questions. One
concerning the --corr_svy-- module and error messages I have been
getting, the second concerning how to obtain a covariance matrix
for complex survey sample data, within Stata.
I am working with a complex survey sample dataset and am using
Stata for some preliminary data analyses (univariate and
multivariate checks for normality, efas) before moving to Mplus for
SEM modeling. I installed the --corr_svy-- module from within Stata
by typing "ssc install corr_svy"
However, in my first attempt below, I got the following error message:
svy, subpop (if race3cat==2 & sex==1 & (riwyes==1 & riwyes <.)):
corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor, pw obs sig
corr_svy is not supported by svy with vce(linearized); see help svy
estimation for a list of Stata estimation commands that are
supported by svy
r(322);
I then attempted to reset the weight and design variables, and run
the --corr_svy--, following the example in the "help" for the
--corr_svy--, excluding my subpop specification.
. svyset clust [pweight=wgtcentriw], strata (stratum) ||_n
Note: stage 1 is sampled with replacement; all further stages will
be ignored
pweight: wgtcentriw
VCE: linearized
Single unit: missing
Strata 1: stratum
SU 1: clust
FPC 1: <zero>
. corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor, pw obs sig
This worked--but it didn't include my subpop specification. I then
tried the same thing with my subpop specifcation and it DIDN'T
work. Any ideas on how to use the corr_svy module to obtain the
correlation matrix, accounting for the weight and design variables
and allowing me to restrict my analyses to my subpop of interest?
corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor [pweight=wgtcent],
strata(stratum) psu(clust) subpop(if race3cat==2 & sex==1 &
(riwyes==1 & riwyes <.)) pw obs sig print(10) star(5)
subpop() does not contain a valid varname
r(198);
. svyset clust [pweight=wgtcentriw], strata (stratum) ||_n
Note: stage 1 is sampled with replacement; all further stages will
be ignored
pweight: wgtcentriw
VCE: linearized
Single unit: missing
Strata 1: stratum
SU 1: clust
FPC 1: <zero>
. corr_svy lesscurt lessresp poorserv notsmart actfraid thkdisho
actbettr callnmes trethara follstor, pw obs sig
In addition, does anyone know how to use the matrix I am trying to
obtain above to obtain a covariance matrix that can be easily
transferred to Mplus or LISREL for CFA and SEM analyses?
Thanks for your consideration,
Ishtar Govia
[email protected]
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
--
--------------------------------------------------------------
Nicholas Winter 434.924.6994 t
Assistant Professor 434.924.3359 f
Department of Politics [email protected] e
University of Virginia faculty.virginia.edu/nwinter w
PO Box 400787, 100 Cabell Hall
Charlottesville, VA 22904
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
--
--------------------------------------------------------------
Nicholas Winter 434.924.6994 t
Assistant Professor 434.924.3359 f
Department of Politics [email protected] e
University of Virginia faculty.virginia.edu/nwinter w
PO Box 400787, 100 Cabell Hall
Charlottesville, VA 22904
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
--
--------------------------------------------------------------
Nicholas Winter 434.924.6994 t
Assistant Professor 434.924.3359 f
Department of Politics [email protected] e
University of Virginia faculty.virginia.edu/nwinter w
PO Box 400787, 100 Cabell Hall
Charlottesville, VA 22904
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/