Hello again (especially StataCorp)
One more query re using -lincom- after -svy- commands in Stata 8. How are
the degrees of freedom calculated? I cannot find anything about this on
Page 21 of -[SVY]-. I ask because a lot of the examples in -[SVY] lincom
for svy- have t-statistics instead of z-statistics, and, as I understand
it, the programs -svymean-, -svyratio- and -svytotal- use a method
dependent on whether -e(complete)- is -complete- or -available-, with a
vector degrees of freedom in the latter case and a scalar degrees of
freedom in the former case.
Best wishes
Roger
At 19:05 08/05/2005, Richard Williams wrote:
At 06:48 PM 5/8/2005 +0100, Roger Newson wrote:
Thanks to Richard for warning us about this little quirk re -lincom-
after -svy- commands in Stata 8. This is controlled by the undocumented
Stata 8 command -is_svy-, which you can find out about by typing
whelp is_svy
Thanks Roger. It is there in Stata 9 as well (hopefully it works with the
new svy prefix?):
http://www.stata.com/help.cgi?is_svy
I wonder if this new svy prefix approach will cause potential problems for
old post-estimation commands, e.g. if you had a post-estimation command
for -logit-, could it potentially have problems if you had run -logit-
with the svy prefix? Or for that matter, with new programs, perhaps you
need to check if svy has been used if that will affect how your program
operates. I'll be glad when I get Stata 9 in a few weeks and can stop
asking and just check these things out for myself.
-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
FAX: (574)288-4373
HOME: (574)289-5227
EMAIL: [email protected]
WWW (personal): http://www.nd.edu/~rwilliam
WWW (department): http://www.nd.edu/~soc
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--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
Division of Asthma, Allergy and Lung Biology
King's College London
5th Floor, Capital House
42 Weston Street
London SE1 3QD
United Kingdom
Tel: 020 7848 6648 International +44 20 7848 6648
Fax: 020 7848 6620 International +44 20 7848 6620
or 020 7848 6605 International +44 20 7848 6605
Email: [email protected]
Website: http://phs.kcl.ac.uk/rogernewson/
Opinions expressed are those of the author, not the institution.
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