[R] Relative Risk in logistic regression
David Winsemius
dwinsemius at comcast.net
Sun Feb 3 16:47:03 CET 2013
On Feb 3, 2013, at 8:15 AM, aminreza Aamini wrote:
> Dear Coleagues ,
> As my friend John mentined,* the measure of association from a
> logistic
> regression is the odds ratio, not the relative risk*. but the point
> is in
> follow-up studies, it is commonly preferred to estimate a risk ratio
> rather
> than an odds ratio. Thats why im looking for RR in logistic models.
> Bytheway thank you all for ur consideration.
> Amin
I agree that the relative risk is generally preferred in presenting
the results of follow-up studies. The question should be: why do you
want to use a logistic link? The technical report out of the
University of Washington Biostatistics Depeartment explains a variety
of approaches including using a log-binomial model and Poisson
regression. Either of those can be done in R with glm. The Poisson
regression model is particularly simple to develop. You should
explain a) what sort of data you have in greater detail and b) your
reasons for using the logistic link when arguably better alternatives
are available if you want a more specific answer.
--
David
>
>
> On Sun, Feb 3, 2013 at 1:42 PM, Michael Dewey
> <info at aghmed.fsnet.co.uk>wrote:
>
>> At 10:49 30/01/2013, aminreza Aamini wrote:
>>
>>> Hi all,
>>> I am very grateful to all those who write to me
>>> 1) how i can obtain relative risk (risk ratio) in logistic
>>> regression
>>> in R.
>>>
>>
>> @TECHREPORT{lumley06,
>> author = {Lumley, T and Kronmal, R and Ma, S},
>> year = 2006,
>> title = {Relative risk regression in medical research: models,
>> contrasts,
>> estimators, and algorithms},
>> number = 293,
>> institution = {{UW} Biostatistics Working Paper Series},
>> keywords = {glm, Poisson},
>> url = {http://www.bepress.com/**uwbiostat/paper293<http://www.bepress.com/uwbiostat/paper293
>> >
>> }
>>
>> }
>>
>>
>> 2) how to obtain the predicted risk for a certain individual using
>>> fitted regression model in R.
>>>
>>> Many thanks, in advance, for your help.
>>>
>>> Amin.
>>>
>>
>> Michael Dewey
>> info at aghmed.fsnet.co.uk
>> http://www.aghmed.fsnet.co.uk/**home.html<http://www.aghmed.fsnet.co.uk/home.html
>> >
>>
>>
>
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>
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David Winsemius, MD
Alameda, CA, USA
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