Stata output files in surveys (proportions) - stata

Question

I need to modify the code below which I'm using on some CPS data to capture insurance coverage. I need to output a file with the percent covered by Census region (there are four). It should look something like this:
region n percent
1 xxx xx
2 xxx xx
3 xxx xx
4 xxx xx
I could live with two rows defining the percentages covered and not covered in each region if necessary, but I really only need the percentage covered.
Here's the code I'm using:
svyset [iw=hinswt], sdrweight(repwt1-repwt160) vce(sdr)
tempname memhold
postfile `memhold' region_rec n prop using Insurance, replace
levelsof region_rec, local(lf)
foreach x of local lf{
svy, subpop(if region_rec==`x' & age>=3 & age<=17): proportion hcovany
scalar forx = `x'
scalar prop = _b[hcovany]
matrix b = e(_N_subp)
matrix c = e(_N)
scalar n = el(c,1,1)
post `memhold' (forx) (n) (prop)
}
postclose `memhold'
use Insurance, clear
list
This is what it produces:
Survey: Proportion estimation Number of obs = 210648
Population size = 291166198
Subpop. no. obs = 10829
Subpop. size = 10965424.5
Replications = 160
_prop_1: hcovany = Not covered
--------------------------------------------------------------
| SDR
| Proportion Std. Err. [95% Conf. Interval]
-------------+------------------------------------------------
hcovany |
_prop_1 | .0693129 .0046163 .0602651 .0783607
Covered | .9306871 .0046163 .9216393 .9397349
--------------------------------------------------------------
[hcovany] not found
r(111);
I can't figure out how to get around the error message at the bottom and get it to save the results. I think a SE and CV would be a desirable feature as well, but I'm not sure how to handle that within the matrix framework.
EDIT: Additional output
+----------------------------------+
| region~c n prop se |
|----------------------------------|
| 1 9640 .9360977 2 |
| 2 12515 .9352329 2 |
| 3 14445 .8769684 2 |
| 4 13241 .8846368 2 |
+----------------------------------+

Answer 1

Try changing _b[hcovany] for _b[some-value-label]. To be clear, the following non-sensical example is similar to your code, but instead of using _b[sex], where sex is a variable, it uses _b[Male], where Male is a value label for sex. Subpopulation sizes and standard errors
are also saved.
clear all
set more off
webuse nhanes2f
svyset [pweight=finalwgt]
tempname memhold
tempfile results
postfile `memhold' region nsubpop maleprop stderr using `results', replace
levelsof region, local(lf)
foreach x of local lf{
svy, subpop(if region == `x' & inrange(age, 20, 40)): proportion sex
post `memhold' (`x') (e(N_subpop)) (_b[Male]) (_se[Male])
}
postclose `memhold'
use `results', clear
list
If we were to use _b[sex] instead of _b[Male], we would get the same r(111) error as in your original post.
For this example, lets see what the matrix e(b), containing the estimated proportions, looks like:
. matrix list e(b)
e(b)[1,2]
sex: sex:
Male Female
y1 .48821487 .51178513
Therefore, if we wanted to extract the proportions for females instead
of males, we could use _b[Female].
Yet another option is to save the estimation result in a matrix and use numerical subscripts:
<snip>
matrix b = e(b)
post `memhold' (`x') (b[1,2])
<snip>
There are other slight changes like the use of inrange and direct use of returned estimation results with post.
Also, you may want to take a look at help _variables and its link:
[U] 13.5 Accessing coefficients and standard errors.