Displaying 20 results from an estimated 300 matches similar to: "coxme and random factors"
2010 Jul 27
0
AIC from coxme
Hi,
I am running the following model:
fit1.full <- coxme(Surv(age_sym1, sym1) ~ sex + lifedxm*sex + (1|famid),
data=bip.surv)
I would like to extract the AIC from that object to calculate the AICC.
However, when I look at str(fit1.full) and summary(fit1.full) (pasted
below) I don't see anything that would allow me to get pull the AIC out
from that object.
Is there a way to retrieve the
2008 Jun 03
0
Summarizing dummy coefficients in sem package
Greetings,
I am working in the sem package on a model with 3 exogenous variables (2
are nominal-categorical), and 4 endogenous, continuous variables. To
use sem with the nominal variables, I created dummy variables. Now, in
my sem output I have estimates for path coefficients for the
relationship between each level of the nominal variables and the
endogenous variables they are associated
2012 Jun 30
2
Significance of interaction depends on factor reference level - lmer/AIC model averaging
Dear R users,
I am using lmer combined with AIC model selection and averaging (in the
MuMIn package) to try and assess how isotope values (which indicate diet)
vary within a population of animals.
I have multiple measures from individuals (variable 'Tattoo') and multiple
individuals within social groups within 4 locations (A, B, C ,D) crucially I
am interested if there are
2011 Jul 08
1
coxme for random effects only model
Dear all,
I have encountered the following problem where coxme seems to allow
model with only random effect in R 2.11.1 but not in R 2.13.0. Following
is the error message using rat example data. Any comment on this is
appreciated.
In R2.13
> library(coxme)
> rat1 <- coxme(Surv(time, status) ~ rx + (1|litter), rats)
> rat0 <- coxme(Surv(time, status) ~ (1|litter), rats)
2012 Feb 03
1
coxme with frailty--variance of random effect?
Dear all,
This probably stems from my lack of understanding of the model, but I
do not understand the variance of the random effect reported in coxme.
Consider the following toy example:
#------------------------------- BEGINNING OF CODE
------------------------------------------------
library(survival)
library(coxme)
#--- Generate toy data:
d <- data.frame(id = c(1:100), #
2011 Aug 02
2
Extract p value from coxme object
Dear R experts;
I am trying to extract the p values from a coxme object (package coxme). I
can see the value in the model output, but I wanted to have the result with
a higher number of decimal places.
I have searched the mailing list and followed equivalent suggestions for
nlme/lme objects, but I wasn't successful.
Thanks;
Catarina
[[alternative HTML version deleted]]
2008 Mar 05
1
coxme - fitting random treatment effect nested within centre
Dear all,
I am using "coxme" function in Kinship library to fit random treatment effect nested within centre. I got 3 treatments (0,1,2) and 3 centres. I used following commands, but got an error.
> ugroup=paste(rep(1:3,each=3),rep(0:2,3),sep='/')
> mat1=bdsmatrix(rep(c(1,1,1,1,1,1,1,1,1),3),blocksize=rep(3,3),dimnames=list(ugroup,ugroup))
>
2007 Apr 20
1
Approaches of Frailty estimation: coxme vs coxph(...frailty(id, dist='gauss'))
Dear List,
In documents (Therneau, 2003 : On mixed-effect cox
models, ...), as far as I came to know, coxme penalize
the partial likelihood (Ripatti, Palmgren, 2000) where
as frailtyPenal (in frailtypack package) uses the
penalized the full likelihood approach (Rondeau et al,
2003).
How, then, coxme and coxph(...frailty(id,
dist='gauss')) differs? Just the coding algorithm, or
in
2012 Feb 19
1
coxme: model simplification using LR-test?
Hi
I'm encountering some problems with coxme
My data:
I'm looking at the survival of animals in an experiment with 3 treatments,
which came from 4 different populations, two of which were infected with a
parasite and two of which were not. I'm interested if infected animals
differe from uninfected ones across treatments.
Factor 1: treatment (3 levels)
Factor 2: infection state
2012 Apr 16
0
warning message: coxme with package multcomp
Hi
I'm encountering an error/warning when doing multiple comparisons with
the package multcomp on a coxme model.
My data:
I'm looking at the removal of brood from the nest according to three
treatments I applied on the brood.
The brood and the workers caring about the brood in the nest, belonged
to different colonies.
Factor: treatment (3 levels: tx,uv,meta)
Random effect 1: origin of
2013 Apr 16
0
Model ranking (AICc, BIC, QIC) with coxme regression
Hi,
I'm actually trying to rank a set of candidate models with an information criterion (AICc, QIC, BIC). The problem I have is that I use mixed-effect cox regression only available with the package {coxme} (see the example below).
#Model1
>spring.cox <- coxme (Surv(start, stop, Real_rand) ~ strata(Paired)+R4+R3+R2+(R3|Individual), spring)
I've already found some explications in
2012 Oct 07
1
variances of random effects in coxme
Dear R users,
I'm using the function coxme of the package coxme in order to build Cox
models with complex random effects. Unfortunately, I sometimes get
surprising estimations of the variances of the random effects.
I ran models with different fixed covariates but always with the same 3
random effects defined by the argument
varlist=coxmeMlist(list(mat1,mat2,mat3), rescale = F, pdcheck = F,
2006 Jul 05
0
Problem with coxme
------------- Begin Forwarded Message -------------
Date: Wed, 5 Jul 2006 09:09:14 -0500 (CDT)
From: Terry Therneau <therneau at mayo.edu>
Subject: RE: Problem with coxme
To: jhz22 at medschl.cam.ac.uk
Cc: R-help at stat.mat.ethz.ch, liulei at virginia.edu, spencer.graves at pdf.com
Content-MD5: BXKVsHtW/1I9mIUqrXBU0g==
The original question involved a strange error message from coxme
2012 Sep 14
1
Correlation between random effects in the package coxme
Hello,
Why the correlation between the random effects is negative?
library(coxme)
rats1 <- coxme(Surv(time, status) ~ (1|litter), rats)
random.effects(rats1)[[1]] #one value for each of the 50 litters
print(rats1)
rats2 <- lmekin(time ~ (1|litter), rats)
fixed.effects(rats2)
random.effects(rats2)[[1]] #one value for each of the 50 litters
print(rats2)
2008 Dec 28
1
Random coefficients model with a covariate: coxme function
Dear R users:
I'm new to R and am trying to fit a mixed model
Cox regression model with coxme function.
I have one two-level factor (treat) and one
covariate (covar) and 32 different groups
(centers). I'd like to fit a random coefficients model, with treat and covar
as fixed factors and a random intercept, random
treat effect and random covar slope per center.
I haver a couple of
2006 Mar 30
1
Random Coefficients using coxme
Hello, I was hoping someone could answer a question for me that may
either be statistical or script related. I don't come from a statistics
background, so I am not positive if I am using the correct nomenclature
or even the correct procedure. Is it possible to model "random
coefficients" in a mixed effects cox-regression using coxme from the
Kinship package? For example, using
2006 Jun 29
2
help with coxme
Hi there,
I have a question on fitting data by coxme. In particular I want to fit a
random intercept and random slope cox model. Using the rats dataset as an
example, I generated another covariate x2 and want to specify a random slope
for x2. Here is my code:
x2=matrix(rep(runif(50), 3), 50, 3)
x2=as.vector(t(x2))
rats2=cbind(rats, x2)
But when I used the coxme function as follows, it gave
2011 Dec 30
0
New version of coxme / lmekin
Version 2.2 of coxme has been posted to CRAN, Windows versions and
mirrors should appear in due course. This is a major update with three
features of note:
1. A non-upwardly compatable change:
Extractor functions: beta= fixed effects, b=random effects
nlme lme4 coxme <2.2 coxme 2.2 lmekin 2.2
------------------------------------------------------
beta
2013 Dec 13
0
Coxme time-dependent covariate
Hi all,
I am using the coxme function to fit random effects survival models. The
base survival models show a typical "J" shaped curve where survival drops
sharply then plateaus over time interval. I want to include a time
covariate which could account for this non-linear decrease in survival over
time. However, I have not found a clear way to do this in the coxme
models. Any
2012 Jun 30
1
How do I extract coefficient standard errors /CI for a "coxme" model
Hello, and thanks for your time
I'm trying to extract standard errors to produce confidence intervals from a
multivariable coxme model object so I can write a function that will print
a summary for some reproducible research. As far as I can glean, the SE is
produced on-the-fly by the print method. I'll dig into the source code if I
have to, but I'd rather not have to.
Any help