Displaying 20 results from an estimated 1000 matches similar to: "Calculating AICc using conditional logistic regression"
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 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+
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
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,
2009 Apr 29
2
AICc
I am fitting logistic regression models, by defining my own link
function, and would like to get AICc values. Using the glm command
gives a value for AIC, but I haven't been able to get R to convert
that to AICc. Is there a code that has already been written for
this? Right now I am just putting the AIC values into an excel
spreadsheet and calculating AICc, likelihood, and AIC
2017 Jun 08
1
stepAIC() that can use new extractAIC() function implementing AICc
I would like test AICc as a criteria for model selection for a glm using
stepAIC() from MASS package.
Based on various information available in WEB, stepAIC() use
extractAIC() to get the criteria used for model selection.
I have created a new extractAIC() function (and extractAIC.glm() and
extractAIC.lm() ones) that use a new parameter criteria that can be AIC,
BIC or AICc.
It works as
2005 Nov 03
1
Help on model selection using AICc
Hi,
I'm fitting poisson regression models to counts of birds in
1x1 km squares using several environmental variables as predictors.
I do this in a stepwise way, using the stepAIC function. However the
resulting models appear to be overparametrized, since too much
variables were included.
I would like to know if there is the possibility of fitting models
by steps but using the AICc
2004 Dec 04
1
AIC, AICc, and K
How can I extract K (number of parameters) from an AIC calculation, both to
report K itself and to calculate AICc? I'm aware of the conversion from AIC ->
AICc, where AICc = AIC + 2K(K+1)/(n-K-1), but not sure of how K is calculated
or how to extract that value from either an AIC or logLik calculation.
This is probably more of a basic statistics question than an R question, but I
thank
2011 Sep 04
2
AICc function with gls
Hi
I get the following error when I try and get the AICc for a gls regression
using qpcR:
> AICc(gls1)
Loading required package: nlme
Error in n/(n - p - 1) : 'n' is missing
My gls is like this:
> gls1
Generalized least squares fit by REML
Model: thercarnmax ~ therherbmax
Data: NULL
Log-restricted-likelihood: 2.328125
Coefficients:
(Intercept) therherbmax
1.6441405
2011 Jul 26
1
nls - can't get published AICc and parameters
Hi
I'm trying to replicate Smith et al.'s
(http://www.sciencemag.org/content/330/6008/1216.abstract) findings by
fitting their Gompertz and logistic models to their data (given in
their supplement). I'm doing this as I want to then apply the
equations to my own data.
Try as a might, I can't quite replicate them. Any thoughts why are
much appreciated. I've tried contacting the
2006 Jul 12
2
AICc vs AIC for model selection
Hi,
I am using 'best.arima' function from forecast package to obtain point forecast for a time series data set. The documentation says it utilizes AIC value to select best ARIMA model. But in my case the sample size very small - 26 observations (demand data). Is it the right to use AIC value for model selection in this case. Should I use AICc instead of AIC. If so how can I modify
2005 Nov 02
1
model selection based on AICc
Dear members of the list,
I'm fitting poisson regression models using stepAIC that appear to
be overparametrized. I would like to know if there is the
possibility of fitting models by steps but using the AICc instead of
AIC.
Best wishes
German Lopez
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,
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
2017 Nov 13
1
Bootstrap analysis from a conditional logistic regression
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Hello
How can I perform
2014 Jun 26
0
AICc in MuMIn package
Hello,
I am modelling in glmmADMB count data (I´m using a negative binomial
distribution to avoid possitive overdispersion) with four fixed and one
random effect. I´m also using MuMIn package to calculate the AICc and also
to model averaging using the function dredge. What I do not understand is
why dredge calculates a different value of the AICc and degrees of freedom
than the function AICc
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
2004 Dec 17
0
behaviour of BIC and AICc code
Dear R-helpers
I have generated a suite of GLMs. To select the best model for each set, I am using the
meta-analysis approach of de Luna and Skouras (Scand J Statist 30:113-128). Simply
put, I am calculating AIC, AICc, BIC, etc., and then using whichever criterion
minimizes APE (Accumulated Prediction Error from cross-validations on all model sets)
to select models.
My problem arises where I
2009 Nov 13
1
plot arguments (PR#14063)
Hi there,
I have recently updated to ver 2.10 (windows - I'm running xp) and find I am
having problems with plot arguments, for e.g.
Using the errbar function the error bars are now in black despite col="red",
the central point is in red though. Axis labels are drawn but not the 'main'
title. No errors are reported.
Using the plot function directly I was only able to
2012 Feb 13
2
R's AIC values differ from published values
Using the Cement hardening data in Anderson (2008) Model Based Inference in
the Life Sciences. A Primer on Evidence, and working with the best model
which is
lm ( y ~ x1 + x2, data = cement )
the AIC value from R is
model <- lm ( formula = y ~ x1 + x2 , data =
cement )
AIC ( model )
64.312
which can be converted to AICc by adding the bias