EZ does it! Extensions of the EZ-diffusion model.
In this rejoinder, we address two of Ratcliff's main concerns with respect to the EZ-diffusion model (Ratcliff, 2008). First, we introduce "robust-EZ," a mixture model approach to achieve robustness against the presence of response contaminants that might otherwise distort parameter estimates. Second, we discuss an extension of the EZ model that allows the estimation of starting point as an additional parameter. Together with recently developed, user-friendly software programs for fitting the full diffusion model (Vandekerckhove & Tuerlinckx, 2007; Voss & Voss, 2007), the development of the EZ model and its extensions is part of a larger effort to make diffusion model analyses accessible to a broader audience, an effort that is long overdue.
Wagenmakers
Eric-Jan
EJ
University of Amsterdam, Amsterdam, The Netherlands. ej.wagenmakers@gmail.com
van der Maas
Han L J
HL
Dolan
Conor V
CV
Grasman
Raoul P P P
RP
D003657:Decision Making; D006801:Humans; D008432:Mathematical Computing; D015233:Models, Statistical; D011594:Psychometrics / Q000706:statistics & numerical data*; D011930:Reaction Time; D012984:Software