[visionlist] Are there any working interactive demos of SDT decision space and ROC space on the web?

Lester Loschky loschky at ksu.edu
Sun Sep 2 15:18:31 -05 2018

Hi Everybody,

For a long time, I've used interactive web-based demonstrations of Signal
Detection Theory (SDT) decision space and ROC space to teach students about
the underlying statistical theory of SDT.  So, I would like to start this
posting by giving a big "Thank You!!" to the folks at Claremont Graduate
University, Ann Bisantz, John Krantz, and Garrett Neske who have made it
possible to do so!  That has been a great educational gift from each of
them to the world wide community.

Having said that, 3 of the 4 ones I ones I know of were written in Java,
and are now no longer able to be run due to being blocked by Java security
(with no possibility of unblocking them).

For example, at Claremont Graduate University, the Web Interface for
Statistics Education (WISE) website had a really nice demo of the SDT
decision space and how it maps onto the ROC space:


However, that Java applet no longer runs due to being blocked by Java
security.  So, you get an error message if you try to run it, which says:
"Application Blocked. Click for details"

I used to be able to add that Java Applet to my trusted Java exceptions in
the Security tab of Preferences in my web browser (Safari).  However, while
I can currently add the WISE website to the exceptions list, I can no
longer add that particular page to the list.  The folks at WISE are aware
of this, and have the following notice about it on their Troubleshooting

Enable JavaScript
> You no longer can unblock Java for specific pages. The applets written in
> JavaScript will work, but the older Java applets will not.

Evidently, that demo is an older Java applet that was not written in

Similarly, I have had the same problem for John Krantz's SDT demos at
Hanover College:

Likewise, there used to be a really nice web-based interactive demo of the
SDT decision space and ROC space by Ann Bisantz at SUNY Buffalo.  However,
I can no longer find it on the web (and if it was written as an older Java
applet, probably would not run now).

Garrett Neske has very kindly shared a nice interactive demo of the SDT
decision space and ROC curve on the Wolfram (Mathematica) Demonstrations
Project, which you can download and run using the Wolfram CDF player.
However, unlike the Claremont WISE and Bisantz interactive demos, it does
not report d' and c.  Having said that, it does give H and F rates out of
1,000 signal present and absent trials each, so one can calculate d' and c
with students in class, but it isn't automatic as with the other
interactive demos.  I guess from an educational standpoint it's a trade-off
between a) fluidity of demonstrating the concepts and b) demonstrating how
to calculate d' and c.  Currently, this is the interactive demo I use in
class (hats off to Garrett).

However, out of curiosity, I'm wondering, are there any other web-based
demos of the SDT decision space and ROC space that currently work?

Best wishes,

Les Loschky

Lester Loschky
Associate Director, Cognitive and Neurobiological Approaches to Plasticity
Department of Psychological Sciences
471 Bluemont Hall
1114 Mid-Campus Dr North
Kansas State University
Manhattan, KS  66506-5302
email: loschky at ksu.edu
research page: https://www.k-state.edu/psych/research/loschkylester.html
lab page: http://www.k-state.edu/psych/vcl/index.html
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