This is an implementation of the PSI method developed by Kontsevich and Tyler (1999).
This package is provided as is. It has been tested and should work without a hitch, but you use this code at your own risk. The zip archive below contains the main .dll, the source code and libraries for embedding the dll in all main programming languages. Enjoy!
Note that for use in Matlab, you will need Release 13 or later, and the GenericDLL addon from Mathworks.
Download the zip-Archive of the current version of PSI (V220.127.116.11, Feb 2 2006).
If you use this for a publication, cite this website as well as the
Kontsevich, LL AND Tyler, CW (1999). Bayesian adaptive estimation of psychometric slope and threshold. Vis Res, 39(16), 2729-37..