similar to: Why is transform="km" the default for cox.zph?

Displaying 20 results from an estimated 2000 matches similar to: "Why is transform="km" the default for cox.zph?"

2007 Sep 27
1
plot(cox.zph())
Hello, I got error message when applying the plot function to the cox.zph object to create the Schoenfeld residual plots. > plot(zph.revasFit[1]) Error in plot.window(xlim, ylim, log, asp, ...) : need finite 'ylim' values In addition: Warning messages: 1: NaNs produced in: sqrt(x$var[i, i] * seval) 2: no non-missing arguments to min; returning Inf in: min(x) 3: no
2006 Mar 31
1
andersen plot vs score process or scaled Schoenfeld residuals to test for proporti0nal hazards
Dear all, I use the Andersen plot to check for proportional hazards assumption for a factor (say x) in the Cox regression model and obtained a straight line that pass through the origin. However, the formal test done by the R-function cox.zph, which is based on the plot of Schonefeld residuals against time, indicates that proportional hazards assumption is violated. Further, a plot of the score
2006 Jan 25
1
cox.zph
Dear R-users, I am sorry if this is obvious. I am testing the proportional hazard assumptions using cox.zph. If i am not wrong, a g(t) function must be assumed. Four possibilities available in R are "km","identity" and "rank". may i know what functions of time are these transformation assuming? Thanks a lot in advance for your wisdom. kind regards, sing yee ling
2007 Sep 27
1
ReL plot(cox.zph())
You report an error message: > plot(zph.revasFit[1]) Error in plot.window(xlim, ylim, log, asp, ...) : need finite 'ylim' values I have never seen this error before, and I cannot guess what causes it. You need to provide more information, and likely a small data set that produces the problem. Perhaps you have an x variable that is a constant? Terry Therneau
2009 Sep 23
2
scaled Schoenfeld residuals
hi sorry if this has been discussed before, but I'm wondering why the scaled Schoenfeld residuals do not follow the defining formula for obtaining them from the ordinary Schoenfeld residuals, but are instead offset by the estimated parameter values. e.g. library(survival) attach(ovarian) sv<-Surv(futime,fustat) f1<-coxph(sv~age+ecog.ps) f1
2010 Feb 23
1
Accelerated failure time interpretation of coefficients
I have one more conceptual question though, it would be fantastic if someone could graciously help out: I am using an accelerated failure time model with time-varying covariates because I assume that my independent variables have a different impact on the chance for a failure at different points in lifetime. For example: High temperature has a different impact on failure in earlier years
2009 Apr 03
2
Schoenfeld Residuals
Dear All, Sorry to bother you again. I have a model: coxfita=coxph(Surv(rem.Remtime/365,rem.Rcens)~all.sex,data=nearma) and I'm trying to do a plot of Schoenfeld residuals using the code: plot(cox.zph(coxfita)) abline(h=0,lty=3) The error message I get is: Error in plot.window(...) : need finite 'ylim' values In addition: Warning messages: 1: In sqrt(x$var[i, i] * seval) : NaNs
2007 Jan 25
0
cox.zph vs log-log survival plot
Hello, Excuse me for a more methodological than technical question. I'm developing a Cox model with 10 covariates. One of them is age (named "eta"). I've checked proportionality with cox.zph with age continuous: > cox.zph(coxph(Surv(TTP,CENSOTTP)~eta)) rho chisq p eta -0.0154 0.0225 0.88 and categorical (eta<60): >
2009 Jun 15
2
Schoenfeld Residuals with tied data
Dear all, I am struggling with calculation of Schoenfeld residuals of my Cox Ph models. Based on the formula as attached, I calculated the Schoenfeld residuals for both non tied and tied data, respectively. And then I validated my results with R using the same data sets. However, I found that my results for non-tied data was ok but the results for tied data were different from R's. How
2004 Apr 14
2
zph / squid syntaxis ?
Hi, I''ve used old ZPH patch under squid 2.4 Stable4 and it works great ! Now I want to patch squid 2.4 stable 5, with new patch, on http://www.it-academy.bg/zph/ I''ve patched and installed squid 2.5 stable 5 succefully, but I can''t get ZPH works. I''m trying with ... $TC class add dev $LANDEV parent 1: classid 1:7 htb rate 1Mbit $TC filter add dev $LANDEV
2006 Dec 21
1
zph patch website broken ?
Hi, I used to patch my squid with ZPH patch on http://www.it-academy.bg/zph/ > The idea behind this patch is to allow classification > of packets generated from the squid cache engine towards > clients. > The classification is based on whether the content is > being served from cache (a cache HIT), or > is being retrieved from a remote server (a cache MISS). Very useful
2006 Nov 14
0
R-Help : Warning messages using plot(cox.zph)
Hi, I get a warning message when I plot cox.zph objects with the transform km and rank, but not with id and log with the same data set. Here's the command: example is a coxph object rk <- cox.zph(example, transform='rank') rk plot(rk) and here's the warning message: Warning messages: 1: suppression des ex-aequos de 'x' in: approx(xx, xtime, seq(min(xx), max(xx),
2003 Jun 11
1
COX PH models for event histories?
This is a question about the use of the Cox proportional hazards model to analyze event histories. I am looking at the responses of sympathetic nervous system activity to a stimulus. The activity I observe is a burst that can only occur once per heart beat cycle (e.g., a binary count). Typically bursts occur in 60-80% of the heart cycles * sensory stimuli can modify these burst probabilities.
2011 Dec 26
2
Problem of COX model with time dependent covariate
Hi all, I am trying to detect association between a covariate and a disease outcome using R. This covariate shows time-varying effect, I add a time-covariate interaction item to build Cox model as follows: COX <- coxph(as.formula("Surv(TIME,outcome)~eGFR_BASE+eGFR_BASE:TIME"),ori.data); coef exp(coef) e(coef) z p eGFR_BASE
2007 Oct 01
3
Apparently Conflicting Results with coxph
Dear List: I have a data frame prepared in the couting process style for including a binary time-dependent covariate. The first few rows look like this. PtNo Start End Status Imp 1 1 0 608.0 0 0 2 2 0 513.0 0 0 3 2 513 887.0 0 1 4 3 0 57.0 0 0 5 3 57 604.0 0 1 6 4 0 150.0 1 0 The outcome
2010 May 21
1
Time dependent Cox model
> ... interactions between covariables and time. A model such as "coxph(Surv(ptime, pstat) ~ age + age*ptime, ...." is invalid -- it is not at all what you think. If cph flags this as an error that is a good thing: I should probably add the same message to coxph. > Is is somewhat sensible to use cox.zph() to investigate which variables need time interaction... The cox.zph
2012 Feb 20
1
Reporting Kaplan-Meier / Cox-Proportional Hazard Standard Error, km.coxph.plot, survfit.object
What is the best way to report the standard error when publishing Kaplan-Meier plots? In my field (Vascular Surgery), practitioners loosely refer to the "10% error" cutoff as the point at which to stop drawing the KM curve. I am interpreting this as the *standard error of the cumulative hazard*, although I'm having a difficult time finding some guidelines about this (perhaps I am
2009 Dec 10
1
PH Model assumption
Hi all, I was trying to test the assumption of proportional hazards assumption, I used the cox.zph function >cox.zph(coxfit6) Results are: rho chisq p x1 -0.0396 1.397 2.37e-01 x2 0.1107 9.715 1.83e-03 x3 -0.0885 7.743 5.39e-03 x4 0.0366 1.092 2.96e-01 x5 0.0242 0.455 5.00e-01 GLOBAL
2006 Apr 03
2
testing proportional hazard in a Cox model including a time-varying covariate
I am using a syntax like coxph(Surv(start, stop, event) ~ X, data) to estimate the effect of X, which may change at each measurement (every 6 months). Is there anyone who knows a way to test the proportional hazard assumption in that case? Thank you in advance Jean-François Boudreau Sherbrooke University [[alternative HTML version deleted]]
2006 Mar 16
1
Problem compiling R-Patched
I downloaded R-Patched today (to see if another problem I want to ask about is still present or if its just me - as per the posting guide). I ran "tools/rsync-recommended" successfully. I then ran "configure --enable-R-shlib" successfully. Then make stops with the following error. gcc -shared -L/usr/local/lib -o tools.so text.o init.o Rmd5.o md5.o -L../../../../lib -lR