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RE: st: Confidence intervals: saving -proportion- estimates to a .dta or .csv file last estimates not found


From   Richard Williams <richardwilliams.ndu@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: Confidence intervals: saving -proportion- estimates to a .dta or .csv file last estimates not found
Date   Fri, 04 Nov 2011 16:17:57 -0500

At 08:45 AM 11/4/2011, Tim Evans wrote:
I've realised I would like the confidence intervals also. But I'm not sure I can find the right values in -ereturn list- that will allow me to calculate the CIs. Can anyone help?

First, you want the square roots of the diagonals of the variance matrix, i.e. the standard errors. After -mim-, this matrix is stored in e(MIM_T). Or, just use the -storebv- option, and you get stuff stored in e(b) and e(V). The (untested) code will be something like this:

matrix bmat = e(MIM_Q)
matrix vmat = e(MIM_T)
forval j = 1/4 {
gen prop`j' = bmat[1,`j']
gen se`j' = bmat[`j', `j'] ** .5
gen lower`j' = se`j' * -1.96 + prop`j'
gen upper`j' = se`j' * 1.96 + prop`j'
}
sum prop* se* lower* upper*
collapse (mean) prop* se* lower* upper*

I am assuming the sample is large and that 1.96 is the appropriate critical value. If small you may need to use the appropriate T value instead. Make sure that the data set matches what the proportion command gave you - it is possible I am doing something wrong here, i.e. given that this is a proportion I might have the formula wrong, in which case you need to hunt down the right formula for the CI.

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Tim Evans
Sent: 04 November 2011 11:39
To: 'statalist@hsphsun2.harvard.edu'
Subject: RE: st: SOLVED! saving -proportion- estimates to a .dta or .csv file last estimates not found

Ignore last post, have just had another google search and found this helpful thread:

http://statalist.1588530.n2.nabble.com/mim-and-parmest-td5013352.html

from Martin Weiss which shows that mim does not store estimates in e(b) rather e(MIM_Q).

Updated code is this:

proportion stage
matrix bmat = e(MIM_Q)
forval j = 1/4 {
gen prop`j' = bmat[1,`j']
}
sum prop*
collapse (mean) prop*

Best wishes

Tim



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Tim Evans
Sent: 04 November 2011 11:31
To: 'statalist@hsphsun2.harvard.edu'
Subject: RE: st: saving -proportion- estimates to a .dta or .csv file last estimates not found

Having tried both methods suggest by Maarten and Richard, I think Richard's will work best, but I have a problem in that I am using this on a multiple imputed dataset. When I run the analysis, I am returned with an error (details below):

mim: proportion stage if _mj>0 & inrange(yydx,1985,1989)
matrix bmat = e(b)

last estimates not found
r(301)

yet when I run this:

proportion stage if _mj>0 & inrange(yydx,1985,1989)
matrix bmat = e(b)
forval j = 1/4 {
gen prop`j' = bmat[1,`j']
}
sum prop*
collapse (mean) prop*


Its absolutely fine - but not what I want.

Any suggestions appreciated.


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Williams
Sent: 03 November 2011 18:27
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: saving -proportion- estimates to a .dta or .csv file

At 11:54 AM 11/3/2011, Tim Evans wrote:
>I'm trying to save and export the proportion estimates I obtain from
>using -proportion- into a useable data file, either .csv or .dta.
>
>However having googled this and looked at help resources with
>-proportion- I don't seem to find what I am after.
>
>How would I return the results from the following code into a data file:
>
>sysuse auto
>proportion rep78 , over(foreign)

The estimates are ereturned in e(b). If nothing else you could
generate variables equal to those values, cut your data set down to
one case, and save under a new name. Something like

sysuse auto
proportion rep78 , over(foreign)
matrix bmat = e(b)
forval j = 1/10 {
gen prop`j' = bmat[1,`j']
}
sum prop*

-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
HOME:   (574)289-5227
EMAIL:  Richard.A.Williams.5@ND.Edu
WWW:    http://www.nd.edu/~rwilliam

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