Displaying 20 results from an estimated 1000 matches similar to: "use of ROCR package (ROC curve / AUC value) in a specific case versus integral calculation"
2012 Dec 19
2
pROC and ROCR give different values for AUC
Packages pROC and ROCR both calculate/approximate the Area Under (Receiver Operator) Curve. However the results are different.
I am computing a new variable as a predictor for a label. The new variable is a (non-linear) function of a set of input values, and I'm checking how different parameter settings contribute to prediction. All my settings are predictive, but some are better.
The AUC i
2009 May 12
1
ROCR: auc and logarithm plot
Hi,
I am quite new to R and I have two questions regarding ROCR.
1. I have tried to understand how to extract area-under-curve value by looking at the ROCR document and googling. Still I am not sure if I am doing the right thing. Here is my code, is "auc1" the auc value?
"
pred1 <- prediction(resp1,label1)
perf1 <- performance(pred1,"tpr","fpr")
plot(
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 <-
2008 Jan 05
1
AUC values from LRM and ROCR
Dear List,
I am trying to assess the prediction accuracy of an ordinal model fit with
LRM in the Design package. I used predict.lrm to predict on an independent
dataset and am now attempting to assess the accuracy of these predictions.
>From what I have read, the AUC is good for this because it is threshold
independent. I obtained the AUC for the fit model output from the c score (c
=
2006 Mar 15
1
How to compare areas under ROC curves calculated with ROCR package
Dear all,
I try to compare the performances of several parameters to diagnose
lameness in dogs.
I have several ROC curves from the same dataset.
I plotted the ROC curves and calculated AUC with the ROCR package.
I would like to compare the AUC.
I used the following program I found on R-help archives :
From: Bernardo Rangel Tura
Date: Thu 16 Dec 2004 - 07:30:37 EST
2005 Sep 22
2
Survey of ROC AUC / wilcoxon test functions
Hi,
I was lately debugging parts of my 'colAUC' function in caTools package, and
in a process looked into other packages for calculating Areas Under ROC
Curves (AUC). To my surprise I found at least 6 other functions:
* wilcox.test
* AUC from ROC package,
* performance from ROCR package,
* auROC from limma package,
* ROC from Epi package,
* roc.area from verification
2007 Nov 21
1
Calculating AUC from ROCR
Dear R-helper,
I am working with ROCR of Tobias Sing et. al. to compare the performances of
logistic and nnet models on a binary response.
I had the performance plots, but I have problem finding out other
performance statistics (eg. MSE/ASE, AUC). Any help on this?
Thanks
Ilham
[[alternative HTML version deleted]]
2008 Mar 06
2
calculate AUC and plot ROC in R
Hi, there:
Could someone tell me a simple function of plot ROC curve and calculate
AUC in R? My setting is very simple, a column of the true binary
response and another column of predicted probabilities.
Thanks!
Yulei
[[alternative HTML version deleted]]
2012 Jul 13
1
ROC curves with ROCR
Hi,
I don't really understand how ROCR works. Here's another example with a
randomforest model: I have the training dataset(bank_training) and testing
dataset(bank_testing) and I ran a randomForest as below:
bankrf<-randomForest(y~., bank_training, mtry=4, ntree=2,
keep.forest=TRUE,importance=TRUE)
bankrf.pred<-predict(bankrf, bank_testing)
2009 Nov 25
0
ROCR Issue: Averaging Across Multiple Classifier Runs in ROC Curve
Dear R-philes,
I am having some trouble averaging across multiple runs of a
classifier in an ROC Curve. I am using the ROCR package and the
plot() method.
First, I initialize a list with two elements where each element is a
list of predictions and labels:
vowel.ROC <- list(predictions=list(), labels=list())
For every run of the classifier, I append the scores and labels to
their
2011 Aug 08
1
Sample size AUC for ROC curves
Hallo!
Does anybody know a way to calculate the sample size for comparing AUC of ROC
curves against 'by chance' with AUC=0.5 (and/or against anothe AUC)?
Thanks!
Karl
2012 Nov 22
3
ROC Curve: negative AUC
Hi all,
does anyone know why the area under the curve (AUC) is negative?
I'm using ROC function with a logistic regression, package Epi.
First time it happens...
Thanks a lot!
Bruno
--
View this message in context: http://r.789695.n4.nabble.com/ROC-Curve-negative-AUC-tp4650469.html
Sent from the R help mailing list archive at Nabble.com.
2006 Mar 20
1
How to compare areas under ROC curves calculated with ROC R package
I might be missing something but I thought that AUC was a measure for
comparing ROC curves, so there is nothing else needed to "compare" them. The
larger AUC is the higher correlation of 2 variables compared. No other
measures or calculations are needed.
Jarek Tuszynski
-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On
2001 Nov 20
0
ROC: AUC test
Is there a statistical test implemented within R to compare the area
under two ROC curves ??
Thanks,
Berthold
-------------- next part --------------
A non-text attachment was scrubbed...
Name: berthold.kramm.vcf
Type: text/x-vcard
Size: 214 bytes
Desc: Card for Dr. Berthold Kramm
Url : https://stat.ethz.ch/pipermail/r-help/attachments/20011120/dc0f7bf1/berthold.kramm.vcf
2008 Sep 20
2
AUC / ROC for presence only.
Dear all,
I have a probability of presence of distribution of a species of interest
(varying from 0 to 1 in continuous form) and I have a set of points
where I know that species really occurs. But I don´t have points of absence.
So, for each true presence I know the estimated presence.
I would like to know how can I compute AUC, taking account these
Available data.
Best wishes,
2011 Jan 20
2
auc function
Hi, there.
Suppose I already have sensitivities and specificities. What is the quick R-function to calculate AUC for the ROC plot? There seem to be many R functions to calculate AUC.
Thanks.
Yulei
[[alternative HTML version deleted]]
2011 Jun 09
1
histogram - density on y axis and restriction to interval [0, 1]
Hello,
To indicate probability densities instead of counts on a histogram, I
specify freq = FALSE.
However, I expect that summing all top y coordinates over all the
intervals of the histogram will provide 1.
1)
v <- c(0.2885, 0.2988, 0.3139, 0.2615, 0.3179, 0.3163, 0.2583, 0.3052,
0.2527, 0.3147, 0.3235, 0.2408, 0.2480, 0.3108, 0.3577, 0.2829, 0.2694,
0.3275, 0.3314, 0.2639, 0.3076,
2009 Jul 25
4
ROCR package question
I use ROCR to plot multiple runs' performance. Using the sample code
as example:
# plot ROC curves for several cross-validation runs (dotted
# in grey), overlaid by the vertical average curve and boxplots
# showing the vertical spread around the average.
data(ROCR.xval)
pred <- prediction(ROCR.xval$predictions, ROCR.xval$labels)
perf <- performance(pred,"tpr","fpr")
2007 Dec 13
2
Function for AUC?
Hello
Is there an easy way, i.e. a function in a package, to calculate the
area under the curve (AUC) for drug serum levels?
Thanks for any advice
--
Armin Goralczyk, M.D.
--
Universit?tsmedizin G?ttingen
Abteilung Allgemein- und Viszeralchirurgie
Rudolf-Koch-Str. 40
39099 G?ttingen
--
Dept. of General Surgery
University of G?ttingen
G?ttingen, Germany
--
http://www.chirurgie-goettingen.de
2011 Apr 27
2
ROCR for combination of markers
Dear list
I have 5 markers that can be used to detect an infection in combination. Could you please advise me how to use functions in ROCR/ other package to produce the ROC curve for a combination of markers?
I have used the following to get ROC statistics for each marker.
pred <- prediction(y$marker1, y$infectn)
perf <-performance(pred,"tpr","fpr")