Displaying 20 results from an estimated 8000 matches similar to: "clogit and general conditional logistic regression"
2011 Dec 21
1
Processing time on clogit
Hi All,
I'm trying to run a conditional logistic regression in R (2.14.0) using
clogit from the survival package. The dataset I have is relatively small
(300 observations) with 25 matched strata- there are roughly 2 controls for
each case, and some strata have multiple case/control groups. When I try to
fit a very simple model with a binary outcome and a single continuous
exposure R seems to
2006 Mar 23
2
clogit question
Hi,
I am playing with
clogit(case~spontaneous+induced+strata(stratum),data=infert)
from clogit help file.
This line works.
1. But, why strata(stratum) doesn't have a coefficient like spontaneous
and induced?
2. When I remove strata(stratum) from the command, this function seems
to keep running forever. Why?
3. I think the equation for clogit looks like
P=1/(1+
2011 Nov 04
1
Counting number of common elements between the rows of two different matrices
Hello
I'm trying to solve this problem without using a for loop but I have so
far failed to find a solution.
I have two matrices of K columns each, e.g. (K=5), and with numbers of
row N_A and N_B respectively
A = (1 5 3 8 15;
2 7 20 11 13;
12 19 20 21 43)
B = (2 6 30 8 16;
3 8 19 11 13)
(the actual matrices have hundreds of thousands of entry, that's why I'm
keen to avoid
2006 Feb 16
1
prediction function for clogit model
Dear R-Help,
I wonder if there is a prediction function for a clogit model which can be
used in the same way as the predict function for the multinom model.
In prediction('multinommodel',testset ...) it is possible to predict the
class or the class probabilities for a testset. There is a predict function
for the coxph model but I cannot find an way to use this to predict the
classes
2011 Dec 12
1
k-folds cross validation with conditional logistic
--begin inclusion --
I have a matched-case control dataset that I'm using conditional
logistic regression (clogit in survival) to analyze. I'm trying to
conduct k-folds cross validation on my top models but all of the
packages I can find (CVbinary in DAAG, KVX) won't work with clogit
models. Is there any easy way to do this in R?
-end inclusion --
The clogit funciton is simply a
2006 Dec 12
1
Calculating AICc using conditional logistic regression
I have a case-control study that I'm analysing using the conditional
logistic regression function clogit from the survival package.
I would like to calculate the AICc of the models I fit using clogit.
I have a variety of scripts that can calculate AICc for models with a
logLik method, but clogit does not appear to use this method.
Is there a way I can calculate AICc from clogit in R?
Many
2012 Oct 18
7
summation coding
I would like to code the following in R: a1(b1+b2+b3) + a2(b1+b3+b4) +
a3(b1+b2+b4) + a4(b1+b2+b3)
or in summation notation: sum_{i=1, j\neq i}^{4} a_i * b_i
I realise this is the same as: sum_{i=1, j=1}^{4} a_i * b_i - sum_{i=j} a_i
* b_i
would appreciate some help.
Thank you.
--
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2011 Feb 27
3
nested case-control study
Hi, I am wondering if there is a package for doing conditional logistic
regression for nested case-control study as described in "Estimation of absolute
risk from nested case-control data" by Langholz and Borgan (1997) where
Horvitz-Thompson sampling weight (log of (number in the risk set divided by the
number sampled)) is used with regression. In SAS Proc Phreg, this is implemented
2011 Nov 07
2
help with formula for clogit
I would like to know if clogit function can be used as below
clogit(group~., data=dataframe)
When I try to use in above format it takes a long time, I would appreciate
some pointers to get multiple combinations tested.
set.seed(100)
d=data.frame(x=rnorm(20)+5,
x1=rnorm(20)+5,
x2=rnorm(20)+5,
x3=rnorm(20)+5,
x4=rnorm(20)+5,
x5=rnorm(20)+5,
x6=rnorm(20)+5,
x7=rnorm(20)+5,
x8=rnorm(20)+5,
2013 Mar 22
1
Integration of vector syntax unknown
Hello,
I'm very new to using R, but I was told it could do what I want. I'm not sure how best to enter the information but here goes...
I'm trying to transfer the following integral into R to solve for ln(gamma_1), on the left, for multiple instances of gamma_i and variable N_i.
gamma_i is, for example, (0, 0.03012048, 0.05000000, 0.19200000, 0.44000000, 0.62566845)
N_i (N_1 or
2003 Jan 22
1
something wrong when using pspline in clogit?
Dear R users:
I am not entirely convinced that clogit gives me the correct result when I
use pspline() and maybe you could help correct me here.
When I add a constant to my covariate I expect only the intercept to change,
but not the coefficients. This is true (in clogit) when I assume a linear in
the logit model, but the same does not happen when I use pspline().
If I did something similar
2010 Apr 20
1
Results from clogit out of range?
Hi,
I'm calculating a conditional logit on some data stratified by group.
My understanding was that a conditional logit by definition returns a
value between 0 and 1 a a probability. Can anyone suggest why I'm
seeing results outside of the {0,1} range??
The call in R is:
m <- clogit(score ~ val_1 + val_2 + strata(group), data=data)
Then
prediction <- predict(m,newdata)
A
2008 May 16
1
Making slope coefficients ``relative to 0''.
I am interested in whether the slopes in a linear model are different
from 0.
I.e. I would like to obtain the slope estimates, and their standard
errors,
``relative to 0'' for each group, rather than relative to some baseline.
Explicitly I would like to write/represent the model as
y = a_i + b_i*x + E
i = 1, ..., K, where x is a continuous variate and i indexes groups
(levels of a
2017 Nov 13
1
Bootstrap analysis from a conditional logistic regression
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Hello
How can I perform
2008 Jul 31
1
clustering and data-mining...
Hi all,
I am doing some experiment studies...
It seems to me that with different combination of 5 parameters, the end
results ultimately converged to two scalars. That's to say, some
combinations of the 5 parameters lead to one end result and some other
combinations of the 5 parameters lead to the other end result (scalar).
I am thinking of this is sort of something like clustering or
2012 Feb 17
3
stepwise selection for conditional logistic regression
Hi,
Is there any function available to do stepwise selection of variables in Conditional(matched) logistic regression( clogit)? step, stepwise etc are failing in case of conditional logistic regression. Please help.
Thanks
P.T. Subha
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2003 May 14
1
mcl models, percentages
I've put two packages for R on my home page at
http://www.xs4all.nl/~jhckx/R/. The "pcnt" package is for multiway
percentage tables. I've posted a first effort called "ctab" on this
group and a request for enhancing "ftable" with percentages on the
wishlist.
The "mcl" package is for estimating multinomial logistic models using
conditional logistic
2016 Apr 26
0
survival::clogit, how to extract residuals for GOF assessment
Hi Folks,
Hopefully this question has enough R and not too much stats to be
appropriate for this list. Based on,* Hosmer et al. 2013. Logistic
regression for matched case-control studies. Applied Logistic
Regression *(eqtn.
7.8)*, *I am assessing GOF of conditional (or matched) logistic regression
models with the *standardized Pearson residuals*. The authors define
?large? as delta chi-squared
2000 Mar 31
2
linear models
Dear R users,
I have a couple of linear model related questions.
1) How do I produce a fixed effect linear model using lme? I saw somewhere
(this may be Splus documentation since I use Splus and R interchangeably)
that using lme(...,random= ~ -1 | groups,...) works, but it gives the same
as lme(...,random= ~ 1 | groups,...), ie. fits a random effect intercept
term.
The reason why I want to do
2006 Jul 29
0
Help with clogit in survival - conditional logistic regression
Dear All:
I have been struggling to run the conditional logistic regression on a
dataset. I am using clogit function in survival package. Here is how the
data is generated. I tried to shorted the data by using the second count
variable but still the clogit did not run. Why I am not able to run clogit
on my dataset. I appreciate any input.
Regards,
Ashraf
age <- c(rep(0,8),rep(1,8))
scc <-