Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-09-05 Thread Teresa Iglesias
David Winsemius wrote: That is different than my understanding of AIC. I thought that the AIC and BIC both took as input the difference in -2LL and then adjusted those differences for the differences in number of degrees of freedom. David! Your words make sense to me now. Sorry

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-29 Thread C. Peng
The likelihood ratio test is more reliable when one model is nested in the other. This true for your case. AIC/SBC are usually used when two models are in a hiearchical structure. Please also note that any decision made made based on AIC/SBC scores are very subjective since no sampling

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-29 Thread Cheng Peng
The likelihood ratio test is more reliable when one model is nested in the other. This true for your case. AIC/SBC are usually used when two models are in a hiearchical structure. Please also note that any decision made made based on AIC/SBC scores are very subjective since no sampling

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-29 Thread Cheng Peng
My suggestion: If compare model 1 and model 2 with model 0 respectively, the (penalized) likelihood ratio test is valid. IF you compare model 2 with model 3, the (penalized) likelihood ratio test is invalid. You may want to use AIC/SBC to make a subjective decision. -- View this message in

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-29 Thread C. Peng
My suggestion for Teresa: If compare model 1 and model 2 with model 0 respectively, the (penalized) likelihood ratio test is valid. IF you compare model 2 with model 3, the (penalized) likelihood ratio test is invalid. You may want to use AIC/SBC to make a subjective decision. -- View this

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-28 Thread Teresa Iglesias
Christopher David Desjardins desja004 at umn.edu writes: Hi, I am running a Cox Mixed Effects Hazard model using the library coxme. I am trying to model time to onset (age_sym1) of thought problems (e.g. hearing voices) (sym1). As I have siblings in my dataset, I have decided to

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-28 Thread David Winsemius
On Aug 27, 2010, at 4:32 PM, Teresa Iglesias wrote: Christopher David Desjardins desja004 at umn.edu writes: Hi, I am running a Cox Mixed Effects Hazard model using the library coxme. I am trying to model time to onset (age_sym1) of thought problems (e.g. hearing voices) (sym1). As I

Re: [R] Question regarding significance of a covariate in a coxme survival model

2010-08-28 Thread Teresa Iglesias
On Sat, Aug 28, 2010 at 8:38 PM, David Winsemius dwinsem...@comcast.netwrote: On Aug 27, 2010, at 4:32 PM, Teresa Iglesias wrote: Christopher David Desjardins desja004 at umn.edu writes: Hi, I am running a Cox Mixed Effects Hazard model using the library coxme. I am trying to model time

[R] Question regarding significance of a covariate in a coxme survival model

2010-08-04 Thread Christopher David Desjardins
Hi, I am running a Cox Mixed Effects Hazard model using the library coxme. I am trying to model time to onset (age_sym1) of thought problems (e.g. hearing voices) (sym1). As I have siblings in my dataset, I have decided to account for this by including a random effect for family (famid). My