Publication: Separating Response-Execution Bias from Decision Bias: Arguments for an Additional Parameter in Ratcliff's Diffusion Model. Two simulation studies in support of including a new parameter in Ratcliff's diffusion model. … read more

Publication: A Fast Numerical Algorithm for the Estimation of Diffusion-Model Parameters. A new algorithmic approach for parameter estimation in Ratcliff's diffusion model. … read more

Publication: Fast-Dm: a Free Programm for Efficient Diffusion Model Analysis. Fast-DM, a flexible and fast computer program, allows estimating all parameters of Ratcliff's diffusion model. … read more

Fast-DM: Fast Diffusion Model Analysis

By Jochen Voss, last updated 2011-08-31

This page contains some information about the program fast-dm. Please note that this is not the official homepage.


Fast-dm is a programm for fast parameter estimation in Ratcliff's (1978) diffusion model. With a Diffusion model data analysis it is possible to analyse data from any fast binary decision task. A diffusion-model data analysis is based on the distributions of both correct and erroneous responses. From these distributions a set of parameters is estimated that allows to draw conclusions about the underlying cognitive processes (Voss, Rothermund, & Voss, 2004).

The implemented algorithm and a bit of background is described in the first of the following two articles, the program itself is described in the second one.


Below is the fast-dm source for download. We offer .tar.gz and .zip archives, the contents of both are identical. Installation instructions are in the file README.

fast-dm version 30.2, 2015-04-17 (bug fix release)

This release fixes some memory leaks found by Valgrind.

fast-dm version 29, 2008-01-13 (bug fix release)

This fixes a problem where for fixed value of z large values of sz where not correctly recognised.

fast-dm version 28, 2007-12-11

This fixes a bug introduced in fast-dm release 27. As a nice side-effect the program is now faster for some parameter settings.

fast-dm version 26, 2007-03-09
fast-dm version 18, 2006-10-29


Copyright © 2011, Jochen Voss. All content on this website (including text, pictures, and any other original works), unless otherwise noted, is licensed under a Creative Commons Attribution-Share Alike 3.0 License.