Displaying 20 results from an estimated 1100 matches similar to: "nested case-control study"
2007 Dec 04
2
weighted Cox proportional hazards regression
I'm getting unexpected results from the coxph function when using
weights from counter-matching. For example, the following code
produces a parameter estimate of -1.59 where I expect 0.63:
d2 = structure(list(x = c(1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 0, 1, 0, 1, 0, 1, 0, 1), wt = c(5, 42, 40, 4, 43, 4, 42,
4, 44, 5, 38, 4, 39, 4, 4, 37, 40, 4, 44, 5, 45, 5, 44, 5), riskset =
2008 Jun 13
2
Quartile regression question
I have data that looks like
lake,loglength,logweight
1,2.369215857,1.929418926
1,2.426511261,2.230448921
1,2.434568904,2.298853076
1,2.437750563,2.298853076
1,2.442479769,2.230448921
1,2.445604203,2.356025857
...
102,2.722633923,3.310268367
102,2.781755375,3.502153893
102,2.836324116,3.683407299
102,2.802773725,3.583312152
102,2.790285164,3.546419267
102,2.806179974,3.599118565
2007 Jan 10
2
SAS and R code hazard ratios
Greetings,
I am new to R and have been comparing CPH survival analysis hazard ratios
between R and SAS PhReg. The binary covariates' HRs are the same, however
the continuous variables, for example age, have quite different HRs
although in the same direction. SAS PhReg produces HRs which are the
change in risk for every one increment change in the independent variable.
How do I
2002 Dec 10
3
clogit and general conditional logistic regression
Can someone clarify what I cannot make out from the
documentation?
The function 'clogit' in the 'survival' package is
described as performing a "conditional logistic regression".
Its return value is stated to be "an object of class clogit
which is a wrapper for a coxph object."
This suggests that its usefulness is confined to the sort of
data which arise in
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,
2009 Dec 02
2
Error when running Conditional Logit Model
Dear R-helpers,
I am very new to R and trying to run the conditional logit model using
"clogit " command.
I have more than 4000 observations in my dataset and try to predict the
dependent variable from 14 independent variables. My command is as follows
clmtest1 <-
clogit(Pin~Income+Bus+Pop+Urbpro+Health+Student+Grad+NE+NW+NCC+SCC+CH+SE+MRD+strata(IDD),data=clmdata)
However, it
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+
2017 Nov 13
1
Bootstrap analysis from a conditional logistic regression
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Hello
How can I perform
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
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
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
2008 Dec 04
1
comparing SAS and R survival analysis with time-dependent covariates
Dear R-help,
I was comparing SAS (I do not know what version it is) and R (version
2.6.0 (2007-10-03) on Linux) survival analyses with time-dependent
covariates. The results differed significantly so I tried to understand
on a short example where I went wrong. The following example shows that
even when argument 'method' in R function coxph and argument 'ties' in
SAS procedure
2008 Aug 31
1
Fitted probabilities in conditional logit regression
Dear R-help,
I'm doing conditional logit regression for a discrete choice model.
I want to know whether there's a way to get the fitted probabilities. In
Stata, "predict" works for clogit, but it seems that in R "predict" does
not.
Thank you very much!
Best wishes.
Sincerely,
Min
--
Min Chen
Graduate Student
Department of Agricultural,
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
[[alternative HTML version deleted]]
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
2012 Nov 24
6
IMPORTANT!!!! PLEASE HELP ME
Hi,
I want to generate 10000 samples from normal distribution with replacement
case and every sample size is 50. What should I do ?
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2003 Aug 15
2
Error in model.frame
I am getting an error that I don't understand, and wonder if anyone
could explain what's going on. I call a function defined thus:
clogit.rds<-function(formula,data,extra.data,response.prob,
na.action=getOption("na.action"),subset=NULL,
control=coxph.control()){
method="exact" # only option for now
mf<-match.call()
2013 Oct 04
2
Survival
Hola.
Una duda....
Alguien sabe si hay algo hecho en R para comprobar si un modelo de supervivencia está bien calibrado?
(usando las pruebas de Nam-D'Agostino o de Gronnesby & Borgan).
Thnks.
Un Saludo,
_____________________________
Miguel Ángel Rodríguez Muíños
Dirección Xeral de Innovación e Xestión da Saúde Pública
Consellería de Sanidade
Xunta de Galicia
http://dxsp.sergas.es
2007 Jul 19
1
R
Hello!
I am using for logistic regression in survey data the svyglm procedure.
I wondered how does the strata effect estimates SE (in addition to the
weights given proportional to population size).
I know that for simple regression measurements of each strata is assumed to
have different variance.
But in a logistic model this is not the case.
Can anyone help me here?
Thank you
Ron
[[alternative
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