Statalist The Stata Listserver


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: RE: Risk differences in Epitab


From   "Newson, Roger B" <[email protected]>
To   <[email protected]>
Subject   st: RE: Risk differences in Epitab
Date   Thu, 9 Feb 2006 09:48:49 -0000

I personally compute confidence intervals for risk differences using the
-somersd- package, downloadable from SSC. If Y is a binary outcome
variable and X is a binary exposure variable, then the command

somersd X Y, tr(z)

gives a confidence interval for the difference in risk between exposed
and unexposed individuals, using the hyperbolic arctangent (Fisher's
z-transform) as a Normalizing and variance-stabilizing transformation.
You can also use the option -tr(asin)- to use the arcsine
transformation.

Hope this helps.

Roger


Roger Newson
Lecturer in Medical Statistics
POSTAL ADDRESS:
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute at Imperial College London
St Mary's Campus
Norfolk Place
London W2 1PG
STREET ADDRESS:
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute at Imperial College London
47 Praed Street
Paddington
London W1 1NR
TELEPHONE: (+44) 020 7594 0939
FAX: (+44) 020 7594 0942
EMAIL: [email protected]
WEBSITE: http://www.kcl-phs.org.uk/rogernewson/
Opinions expressed are those of the author, not of the institution.


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Edward Norton
Sent: 09 February 2006 04:02
To: [email protected]
Subject: st: Risk differences in Epitab

Statalist,
    I would like to compute a risk difference, instead of the default 
risk ratio, using the -cs- command in epitab.  However, when I try to 
run commands like

gen ones = 1
cs y x, by(a b c) standard(ones) rd

Stata 9.0 returns a error of "invalid sytax" number 198.  The same 
command without "rd" (meaning the default risk ratio) works fine.
    Any suggestions about how to compute risk differences would be 
appreciated.
    Edward
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index