The EZ-Diffusion Model

This is a small JavaScript program that computes the parameter values for the EZ-diffusion model (for details consult the manuscript referenced at the bottom of this page).

Note. If you have calculated the RT mean and RT variance based on data measured in milliseconds, you need to take some care when transforming these quantities to seconds. The RT mean  in seconds is obtained from the RT mean in milliseconds by simply dividing by 1000, but the RT variance in seconds-squared is obtained from the RT variance in milliseconds by dividing by 1000 times 1000 (i.e., 1,000,000).

RT Mean (in seconds!): RT Variance (in seconds-squared!): Proportion Correct (0-1):
Drift rate v: Boundary separation a: Nondecision time Ter
(in seconds):

Scaling parameter s:
When using this program, please acknowledge the following source:

Wagenmakers, E.-J., van der Maas, H. L. J., & Grasman, R. P. P. P. (2007). An EZ-diffusion model for response time and accuracy. Psychonomic Bulletin & Review, 14, 3-22.