Displaying 20 results from an estimated 3000 matches similar to: "Receiver Operator Characteristic curve"
2008 Sep 08
2
ROC curve from logistic regression
I know how to compute the ROC curve and the empirical AUC from the logistic
regression after fitting the model.
But here is my question, how can I compute the standard error for the AUC
estimator resulting form logistic regression? The variance should be more
complicated than AUC based on known test results. Does anybody know a
reference on this problem?
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2005 Jul 19
1
ROC curve with survival data
Hi everyone,
I am doing 5 years mortality predictive index score with survival analysis using a Cox proportional hazard model where I have a continous predictive variable and a right censored response which is the mortality, and the individuals were followed a maximum of 7 years.
I'd like to asses the discrimination ability of survival analysis Cox model by computing a ROC curve and area
2009 Oct 22
5
How to calculate the area under the curve
Hi all,
I would like to calculate the area under the ROC curve for my predictive
model. I have managed to plot points giving me the ROC curve. However, I do
not know how to get the value of the area under.
Does anybody know of a function that would give the result I want using an
array of specificity and an array of sensitivity as input?
Thanks,
Olivier
--
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2011 May 12
2
Can ROC be used as a metric for optimal model selection for randomForest?
Dear all,
I am using the "caret" Package for predictors selection with a randomForest model. The following is the train function:
rfFit<- train(x=trainRatios, y=trainClass, method="rf", importance = TRUE, do.trace = 100, keep.inbag = TRUE,
tuneGrid = grid, trControl=bootControl, scale = TRUE, metric = "ROC")
I wanted to use ROC as the metric for variable
2005 Jan 11
1
Standard error for the area under a smoothed ROC curve?
Hello,
I am making some use of ROC curve analysis.
I find much help on the mailing list, and I have used the Area Under the
Curve (AUC) functions from the ROC function in the bioconductor project...
http://www.bioconductor.org/repository/release1.5/package/Source/
ROC_1.0.13.tar.gz
However, I read here...
http://www.medcalc.be/manual/mpage06-13b.php
"The 95% confidence interval for
2010 Dec 09
1
error in lrm( )
Dear Sir or Madam?
I am a doctor of urology,and I am engaged in developing a nomogram of bladder cancer. May I ask for your help on below issue?
I set up a dataset which include 317 cases. I got the Binary Logistic Regression model by SPSS.And then I try to reconstruct the model
?lrm(RECU~Complication+T.Num+T.Grade+Year+TS)? by R-Project,and try to internal validate the model through
2009 Jul 17
1
c-index validation from Design library
Hi Group,
I have a question about obtaining the bias-corrected c-index using
validate from the Design library.
As an example, consider the example from help page:
library(Design)
?validate.lrm
n <- 1000
age <- rnorm(n, 50, 10)
blood.pressure <- rnorm(n, 120, 15)
cholesterol <- rnorm(n, 200, 25)
sex <- factor(sample(c('female','male'),
2010 Jan 22
2
Computing Confidence Intervals for AUC in ROCR Package
Dear R-philes,
I am plotting ROC curves for several cross-validation runs of a
classifier (using the function below). In addition to the average
AUC, I am interested in obtaining a confidence interval for the
average AUC. Is there a straightforward way to do this via the ROCR
package?
plot_roc_curve <- function(roc.dat, plt.title) {
#print(str(vowel.ROC))
pred <-
2002 Feb 01
4
ROC curves using R
I did some serach around. It seems that ROC curve computation is not
supported on R. Anyone has some leads? Thanks.
Jason
=====
Jason G. Liao, Ph.D.
Division of Biometrics
UMDNJ School of Public Health
335 George Street, Suite 2200
New Brunswick, NJ 08903-2688
phone (732) 235-9748, fax (732) 235-9777
http://www.geocities.com/jg_liao
__________________________________________________
Great
2004 Jun 04
1
use of "rcorr.cens" with binary response?
Dear R-helpers,
I recently switched from SAS to R, in order to model the occurrence of
rare events through logistic regression.
Is there a package available in R to calculate the Goodman-Kruskal
Gamma?
After searching a bit I found a function "rcorr.cens" which should do
the job, but it is not clear to me how to define the input vectors? Is
"x" a vector with the fitted
2006 Apr 21
1
rcorrp.cens
Hi R-users,
I'm having some problems in using the Hmisc package.
I'm estimating a cox ph model and want to test whether the drop in
concordance index due to omitting one covariate is significant. I think (but
I'm not sure) here are two ways to do that:
1) predict two cox model (the full model and model without the covariate of
interest) and estimate the concordance index (i.e. area
2011 Jun 13
1
Somers Dyx
Hello R Community,
I'm continuing to work through logistic regression (thanks for all the help on score test) and have come up against a new opposition.
I'm trying to compute Somers Dyx as some suggest this is the preferred method to Somers Dxy (Demaris, 1992). I have searchered the [R] archieves to no avail for a function or code to compute Dyx (not Dxy). The overview of Hmisc has
2009 Sep 08
1
rcorrp.cens and U statistics
I have two alternative Cox models with C-statistics 0.72 and 0.78. My question is if 0.78 is significantly greater than 0.72. I'm using rcorrp.cens. I cannot find the U statistics in the output of the function. This is the output of the help example:
> x1 <- rnorm(400)
> x2 <- x1 + rnorm(400)
> d.time <- rexp(400) + (x1 - min(x1))
> cens <- runif(400,.5,2)
> death
2011 Feb 14
1
Optimal Y>=q cutoff after logistic regression
Hi,
I understand that dichotimization of the predicted probabilities after
logistic regression is philosophically questionable, throwing out
information, etc.
But I want to do it anyway. I'd like to include as a measure of fit %
of observations correctly classified because it's measured in units
that non-statisticians can understand more easily than area under the
ROC curve, Dxy, etc.
2004 Nov 30
3
About ROC curves
Hi, Dear all R users:
Does someone know whether R can calculate the Receiver Operating
Characteristic (ROC) Curves? I didn't find it from the packages.
Thanks a lot.
--- Xin
2009 Jul 17
2
Getting the C-index for a dataset that was not used to generate the logistic model
Does anyone know how to get the C-index from a logistic model - not using
the dataset that was used to train the model, but instead using a fresh
dataset on the same model?
I have a dataset of 400 points that I've split into two halves, one for
training the logistic model, and the other for evaluating it. The structure
is as follows:
column headers are "got a loan" (dichotomous),
2012 Sep 20
1
validate.lrm - confidence interval for boostrap-corrected AUC ?
Hi
Does anyone know whether the rms package provides a confidence interval for
the bootstrap-corrected Dxy or c-index?
I have fitted a logistic model, and would like to obtain the 95% confidence
interval of the bootstrap-corrected area under the ROC curve estimate.
Thanks.
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2018 Apr 08
2
Syntax roccomp-using R
*Dear Bert, *
Thank you very much for your feedback and the useful link https://rseek.org/
and https://www.r-bloggers.com/calculating-auc-the-area-under-a-roc-curve/.
Actually, I want to know different performance between Stata and R, in
multilevel logistic regression. For this purposes, I replicate ".do" file
use Stata in
2008 Feb 21
2
how to create ROC curve for 2 dimensional classifiers
Hi,
I understand for 1 d classifiers, you can use ROCR package.
Is there a package you can plot ROC curve for 2d classifiers? One of
my colleagues asked me about this. I have been quite puzzled,
conceptually, how you can do the ROC curve for 2d classifiers. Can
someone share his/her knowledge or experience?
Thanks in advance.
--
Waverley @ Palo Alto
2005 Nov 25
3
obtaining a ROC curve
Hello,
I have a classification tree. I want to obtain a ROC curve for this test. What is the easiest way to obtain one?
-Anjali
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