ROC Analysis

Web-based Calculator for ROC Curves


To access this page, you may use the link www.jrocfit.org.
John Eng, M.D.
Russell H. Morgan Department of Radiology and Radiological Science
Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

      
 

Instructions:  This web page calculates a receiver operating characteristic curve from data pasted into the input data field below. To analyze your data, use the following steps to fill out the data form on this page.
  1. Select the data format. (See explanation of data formats.)
  2. Paste or enter your data into the "Input Data" field or click the "Paste Example Data" button. Data may be pasted from programs such as Microsoft Excel or Word.
  3. Enter the number of rating categories. (See explanation of data formats.) This is not needed for the example data or Format 5.
  4. Click the "Run Program" button.
  5. To export the ROC plot to Microsoft Word or Excel, see instructions below.
Computer requirements:  Reasonably up-to-date web browser and Java versions are required. Due to its continuing evolution, the latest Java version is highly recommended. Note that Java is no longer installed by default on some new computers, so manual installation of Java may be required.

Running the first time:  When loading this page for the first time, you may need to click a button on this page to enable your Java plug-in and give permission to run JROCFIT. These security messages are normal.
       Suggested citation:  The citations below conform to the styles used by the National Library of Medicine and the American Psychological Association, respectively.
  1. Eng J. ROC analysis: web-based calculator for ROC curves. Baltimore: Johns Hopkins University [updated 2014 March 19; cited <date>]. Available from: http://www.jrocfit.org.
  2. Eng, J. (n.d.). ROC analysis: web-based calculator for ROC curves. Retrieved <date>, from http://www.jrocfit.org.
Acknowledgment:  This web page contains JROCFIT and JLABROC4, Java programs for calculating receiver operating characteristic (ROC) curves. JROCFIT performs calculations for discrete ratings data, and JLABROC4 performs calculations for continuously distributed data. JROCFIT and JLABROC4 are direct translations of the ROCFIT and LABROC4 programs, respectively. The latter two were Fortran programs developed by the late Charles Metz and colleagues at the University of Chicago. JROCFIT and JLABROC4 reproduce all output of the original programs. See below for program translation details.

Problems:  This page may not work with older browser or Java versions. If you have trouble and cannot install the latest browser and Java versions, you can try the earlier version or even earlier version of this page. Please send any bugs, questions, comments, or suggestions to electronic mail will be answered.
 


Data Format:  Format 1   Format 2   Format 3   Format 4   Format 5  

Number of Rating Categories:       (Not needed for example data or for Format 5.)
 




 
Input Data:  (paste or enter)  Program Output:  (may be copied and pasted into other programs)

ROC Curve  Summary Statistics:  Points for Plotting:  (copy & paste to Excel)

ROC Curve Type:   Fitted   Empirical


Key for the ROC Plot
RED symbols and BLUE line:  Fitted ROC curve.
GRAY lines:  95% confidence interval of the fitted ROC curve.
BLACK symbols ± GREEN line:  Points making up the empirical ROC curve (does not apply to Format 5).
 

 
Exporting the ROC plot to Word or Excel:  Due to limitations of web technology, there is no one-step method for exporting the ROC plot to Microsoft Word or Excel. However, two methods are available for exporting:
  1. Select all of the text in the "Points for Plotting" field, which is located to the right of the graph above. Copy and paste this text into Microsoft Excel. In Excel, create a graph from the data by usual methods. This is a good way to obtain a publication-quality graph of the ROC curve.
  2. Copy a snapshot of the browser window by pressing Alt-PrintScreen, switch to the Microsoft Word window, and paste the image by pressing Control-V. In Word, you need to use Format...Picture (or the cropping tool from the Picture toolbar) to crop and scale the image as needed.
        
Program translation details:  The colored box at the top of this page contains JROCFIT and JLABROC4, programs for fitting receiver operating characteristic (ROC) curves using the maximum likelihood fit of a binormal model. JROCFIT and JLABROC4 are literal Java translations of the Fortran source code for ROCFIT and LABROC4, programs developed and maintained by Dr. Charles Metz and colleagues at the University of Chicago. During translation, data input routines were added to JROCFIT and JLABROC4 in order to provide a more convenient user interface. The translation was performed with kind permission from Dr. Metz, but neither he nor his colleagues were otherwise involved in the translation, nor do they share any responsibility for the translation's accuracy. While the translation was performed as carefully as possible, the author and Johns Hopkins University assume no responsibility for the accuracy of the programs' operation, regardless of cause.
 (Page last updated: 19 March 2014)