Re: [R] poisson regression with robust error variance ('eyestudy

From: Ted Harding <>
Date: Thu, 08 May 2008 14:38:40 +0100 (BST)

The below is an old thread:

On 02-Jun-04 10:52:29, Lutz Ph. Breitling wrote:
> Dear all,
> i am trying to redo the 'eyestudy' analysis presented on the site
> with R (1.9.0), with special interest in the section on "relative
> risk estimation by poisson regression with robust error variance".
> so i guess rlm is the function to use. but what is its equivalent
> to the glm's argument "family" to indicate 'poisson'? or am i
> somehow totally wrong and this is not applicable here?
> thx a lot-
> lutz
> =============================
> Lutz Ph. Breitling, CMd
> Unité des Recherches Médicale
> Hôpital Albert Schweitzer
> B.P. 118 Lambaréné (GABON)

It seems it may have led to a solution. However, I have tried to trace through the thread in the R-help archives, and have failed to find anything which lays out how a solution can be formulated.[*]

I'm interested in the same question. Basically, if I fit a GLM to Y=0/1 response data, to obtain relative risks, as in

  GLM <- glm(Y ~ A + B + X + Z, family=poisson(link=log))

I can get the estimated RRs from

  RRs <- exp(summary(GLM)$coef[,1])

but do not see how to implement confidence intervals based on "robust error variances" using the output in GLM.

If there was a solution arrived at, can someone spell it out for me, please?

With thanks,

[*] PS: I did the "R Site Help and Archive Search" on "eyestudy", and got 18 hits, of which 6 were postings on that thread.

However, despite the fact that I requested the results to be sorted "by date, earliest on top", they seem to come out in somewhat random order:

Sat Jun 5 14:47:26 2004 (Frank E. Harrell)
Wed Jun 9 13:06:04 2004 (Lutz Ph. Breitling)
Sat Jun 5 13:51:45 2004 (Lutz Ph. Breitling)
Wed Jun 2 18:24:54 2004 (Frank E. Harrell)
Wed Jun 2 12:44:45 2004 (Lutz Ph. Breitling) [the initial posting]
Wed Jun 2 16:36:43 2004 (Thomas Lumley)

This made it difficult to follow the thread, and indeed I wonder if all the postings have been found. Does Namazu have problems in this respect? (And, if I click on "How to search", I get the response "You don't have permission to access /namazu.html on this server.")

And, if I click on "Contemporary messages sorted: ... by thread" I get the response:
"The requested URL /R/Rhelp02a/archive/index.html was not found  on this server."

E-Mail: (Ted Harding) <> Fax-to-email: +44 (0)870 094 0861
Date: 08-May-08                                       Time: 14:38:36
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