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
rathe
Amin,
It is incorrect to use the relative risk as a measure of association in a
logistic regression. The measure of association in a logistic regression is
the odds ratio. The odds ratio is an approximation of the relative risk. The
approximation becomes progressively better as the disease beco
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
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 regres
Ivan,
In reference to your part 2), in 1989 Li and Duan published a paper where
they examined the effect of using the "wrong" link function (
http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&handle=euclid.aos/1176347254).
The short version is that they found that in common model
Dear colleagues, I have 2 points: One opinion and one question.
1)
In one paper in a peer-reviewed journal, I read about the idea of using a
logit regression as a surrogate for the log-binomial, just adding the
numerator to the denominator ...
It’s tempting to immediately get the RR instead of OR
I am curious why one would want risk ratios. Unlike odds ratios, they are
not interpretable without reference to the base risk. For example a risk
ratio of 2 cannot possibly apply to anyone with a starting risk exceeding
1/2.
I think it is most helpful to use one of the existing nomograms to sho
On Jan 30, 2013, at 5:49 AM, 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.
2) how to obtain the predicted risk for a certain individual using
fitted regression model in R.
You ob
On 01/30/2013 11:26 AM, John Sorkin wrote:
If you use a log link, you are not, I believe, performing a logistic
regression!
I guess strictly speaking, that is true. I was being a little sloppy in
terminology.
"Kevin E. Thorpe" 1/30/2013 11:22 AM >>>
On 01/30/2013 11:17 AM, John Sorkin wr
If you use a log link, you are not, I believe, performing a logistic regression!
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD
On 01/30/2013 11:17 AM, John Sorkin wrote:
I am not sure why one would want a relative risk from a logistic
regression. The measure of association from a logistic regression is the
odds ratio, not the relative risk.
John
Yes, the natural measure, when using the logit link, is the OR. I
alway
I am not sure why one would want a relative risk from a logistic regression.
The measure of association from a logistic regression is the odds ratio, not
the relative risk.
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Divisio
On 01/30/2013 09:02 AM, nalluri pratap wrote:
Relative risk = exp(coef(model))
Only if you fit using the log link. Using the logit link, this gives
odds ratios.
--- On Wed, 30/1/13, aminreza Aamini wrote:
From: aminreza Aamini
Subject: [R] Relative Risk in logistic regression
To: "R-h
Example from linear regression help (?lm)
ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
group <- gl(2,10,20, labels=c("Ctl","Trt"))
weight <- c(ctl, trt)
lm.D9 <- lm(weight ~ group)
lm.D90 <- lm(weight ~ group - 1)
predic
Relative risk = exp(coef(model))
--- On Wed, 30/1/13, aminreza Aamini wrote:
From: aminreza Aamini
Subject: [R] Relative Risk in logistic regression
To: "R-help"
Date: Wednesday, 30 January, 2013, 4:19 PM
Hi all,
I am very grateful to all those who write to me
1) how i can obtain relative
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