Re: st: Re: [Stata 9] Anova and control

[Roger Newson <roger.newson@kcl.ac.uk>]

At 13:25 25/05/2005, Paul Fenner wrote:
> I have an anova where 3 treatments have to be compared to a control. When 
> I used to use SAS I used Dunnett's multiple comparison with the control 
> option, but  cannot find any similar procedure in Stata. I was considering 
> using the test option and compare each treatment with the control but I am 
> a concerned that this does not take into account the mutiple comparisons. 
> I would be grateful for any suggestions on how to approach this problem.
A wide range of multiple-test procedures (including the Sidak procedure, on 
which I think that Dunnett's procedure is probably based) is available 
using the -smileplot- package, downloadable from SSC. This can be used 
together with the -parmest- package (also downloadable from SSC), in a way 
documented in Newson et al. (2003). Use the -ssc- command to download 
things from SSC.

I hope this helps.

Best wishes

Roger


References

Newson, R. and the ALSPAC Study Team. 2003. Multiple-test procedures and 
smile plots.
The Stata Journal 3(2): 109-132. Also downloadable from Roger Newson's 
website at
http://www.kcl-phs.org.uk/rogernewson.


--
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: roger.newson@kcl.ac.uk
Website: http://phs.kcl.ac.uk/rogernewson/

Opinions expressed are those of the author, not the institution.

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