Displaying 20 results from an estimated 7000 matches similar to: "Validating a Cox model on an external set"
2008 Apr 09
2
How to estimate a hazard ratio using an external hazard function
Hi,
I would like to compare the hazard functions of two samples using the
Cox proportional hazards model. For sample 1 I have individual time-to-
event data. For sample 2 I don't have individual data, but grouped
data that allows to obtain a hazard function.
I am wondering if there is an R function that allows to obtain a
hazard ratio of the two hazard funtions (under the
2013 Apr 29
3
Comparing two different 'survival' events for the same subject using survdiff?
I have a dataset which for the sake of simplicity has two endpoints. We would like to test if two different end-points have the same eventual meaning. To try and take an example that people might understand better:
Lets assume we had a group of subjects who all received a treatment. The could stop treatment for any reason (side effects, treatment stops working etc). Getting that data is very
2008 Dec 04
1
Comparing survival curves with "survdiff" "strata" help
ExpeRts,
I'm trying to compare three survival curves using the function "survdiff" in the survival package. Following is my code and corresponding error message.
> survdiff(Surv(st_months, status) ~ strata(BOR), data=mydata)
Error in survdiff(Surv(st_months, status) ~ strata(BOR), data = mydata) :
No groups to test
When I check the "strata" of the variable. I get .
2013 Nov 20
4
How to stop Kaplan-Meier curve at a time point
Hello R users
I have a question with Kaplan-Meier Curve with respect to my research. We
have done a retrospective study on fillings in the tooth and their survival
in relation to the many influencing factors. We had a long follow-up time
(upto 8yrs for some variables). However, we decided to stop the analysis at
the 6year follow up time, so that we can have uniform follow-up time for
all the
2005 Nov 23
1
survdiff for Left-truncated and right-censored data
dear all,
I would like to know whether survdiff and survReg function in the
survival package work for left-truncated and right-censored data.
If not, what other functions can i use to make comparison between two
survival curves with LTRC data.
thanks for any help given
sing yee
2010 Dec 31
3
survexp - example produces error
Dear All,
reposting, because I did not find a solution, maybe someone could
check the example below.
It's taken from the help page of survdiff. Executing it, gives the error
"Error in floor(temp) : Non-numeric argument to mathematical function"
best regards,
Heinz
library(survival)
## Example from help page of survdiff
## Expected survival for heart transplant patients based
2009 May 21
1
Changelog for the survival package
> Several changes in print.survfit, plot.survfit and seemingly in the structure
> of ratetabels effect some of my syntax files.
> Is there somewhere a documentation of these changes, besides the code itself?
I agree, the Changelog.09 file is not as comprehensive as one would like.
Specific comments:
1. The ratetables were recently changed to accomodate a new option. I thought
2012 Oct 19
2
Question about survdiff in for-loop.
Hi everyone!!
I have dataset composed of a numbers of survival analyses.
( for batch survival analyses by using for-loop) .
Here are code !!
#######
dim(svsv)
Num_t<-dim(svsv)
Num<-Num_t[2] # These are predictors !!
names=colnames(svsv)
for (i in 1:Num )
{
name_tt=names[i]
survdiff(Surv(survival.m, survival) ~ names[i], data=svsv)
fit.Group<-survfit(Surv(survival.m, survival) ~
2012 Jan 10
1
Lapack routine dgesv: system is exactly singular
Hi
I have a problem with this error, I have searched the archives and found
previous discussion about this, can I cannot understand how the explanations
apply to what I am trying to do.
I am trying to do Log_rank Survival analysis, I have included tables and str
command, is it a factor/integer problem? If so how do I correct this, as all
my attempt to recode the data have failed.
>
2010 Jul 07
1
Appropriateness of survdiff {survival} for non-censored data
I read through Harrington and Fleming (1982) but it is beyond my
statistical comprehension. I have survival data for insects that have
a very finite expiration date. I'm trying to test for differences in
survival distributions between different groups. I understand that
the medical field is most often dealing with censored data and that
survival analysis, at least in the package survival,
2004 May 04
2
Epidemiology Tools
Hi all,
Please help on this. We will be teaching epidemiology using opensource
software. What are R built-in functions or functions in available packages
that are capable of doing these:
a) Logistic regression (glm?)
b) Conditional logistic regression
c) Logistic regression with random effects
d) Beta-binomial regression
e) Poisson regression
f) Weibull regression (eha?)
g) Exponential
2016 Aug 11
3
Comparación de probabilidades de supervivencia en R
Estimados miembros de la lista,
Estoy haciendo una análisis de supervivencia con R. Adjunto mis datos.
Quiero analizar la supervivencia de 5 grupos diferentes y compararla. Para
ello estoy utilizando el paquete survival.
> s = Surv(c$tiempo, c$estado)
> f = survfit(s ~ tratamiento, data = c)
> d = survdiff(s ~ tratamiento, data = c)
> d
Call:
survdiff(formula = s ~ tratamiento,
2005 Aug 28
2
stratified Wilcoxon available?
Dear All,
is there a stratified version of the Wilcoxon test (also known as van
Elteren test) available in R?
I could find it in the survdiff function of the survival package for
censored data. I think, it should be possible to use this function creating
a dummy censoring indicator and setting it to not censored, but may be
there is a better way to perform the test.
Thanks,
Heinz T??chler
2009 Sep 16
2
Teasing out logrank differences *between* groups using survdiff or something else?
R Folk:
Please forgive what I'm sure is a fairly na?ve question; I hope it's clear.
A colleague and I have been doing a really simple one-off survival analysis,
but this is an area with which we are not very familiar, we just happen to
have gathered some data that needs this type of analysis. We've done quite
a bit of reading, but answers escape us, even though the question below
2018 Mar 05
2
backquotes and term.labels
A user reported a problem with the survdiff function and the use of variables that contain
a space.? Here is a simple example.? The same issue occurs in survfit for the same reason.
lung2 <- lung
names(lung2)[1] <- "in st"?? # old name is inst
survdiff(Surv(time, status) ~ `in st`, data=lung2)
Error in `[.data.frame`(m, ll) : undefined columns selected
In the body of the code
2007 Jul 08
2
Making Gehan-Breslow test for Survival data
Hi all,
The survivals functions can be tested by the Log-rank test and others, for
example the Gehan-Breslow. The graham breslow work with the alpha values.
But I don't know how is the Gehan-Breslow test with R. Somebody know a
type function?.. or other suggestions? Any help will be really
appreciated
Jos? Bustos
Marine Biologist
Master Apllied Stat Program
University of Concepci?n
2009 Aug 03
1
survdiff for left-truncated data?
Hi
Does anyone know if there is a function like survdiff which can also handle
left-truncated and right-censored data? When I use it on left-truncated and
right-censored data I get an error message saying Right censored data only.
Many thanks
Rajen
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2004 Sep 22
1
Cox proportional hazards model
Good afternoon,
I am currently trying to do some work on survival analysis.
- I hope to seek your advice re: 2 questions (1 general and 1 specific)
(1) I'm trying to do a stratified Cox analysis and subsequently
plot(survfit(object)). It seems to work for some strata, but not for
others.
I have tumor grade, which is a range of 1 - 4.
When I divide this range of 1:4 into 2 groups, it
2007 May 08
1
censoring
in R when carring out the log rank test is the censored variable denoted by 1 or 0 or its of no consequence.
thanks
---------------------------------
always stay connected to friends.
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2012 Oct 16
2
R Kaplan-Meier plotting quirks?
Hello. I apologize in advance for the VERY lengthy e-mail. I endeavor to
include enough detail.
I have a question about survival curves I have been battling off and on for
a few months. No one local seems to be able to help, so I turn here. The
issue seems to either be how R calculates Kaplan-Meier Plots, or something
with the underlying statistic itself that I am misunderstanding. Basically,