[logo] bootstrap-software.org

psignifit -> download | publications | FAQ

psignifit used to be called "psychofit"...

... which seemed like the obvious name for software that fits psychometric functions. Clearly it was too obvious, because it turned out that others had used it before, to describe some psychological profiling techniques used in criminal investigations, as well as for psychophysical software. David Panek and J. C. Stevens released psycho-acoustical software called "psychofit" in 1965 and 1969, and Lewis O. Harvey also has a psychometric-function fitting package of this name (see below).

So as not to cause confusion or tread on any toes, I thought it a good idea to think up a new name, and the move to seemed like a good time to do it. Admittedly sounds a little too much like it was dreamt up in the marketing department of an American corporation, but it's beginning to grow on me - it has the advantage of emphasizing the importance of significance testing in psychometric-function fitting, which is the central idea of the project.

Any of our publications written before March 2002 still refer to the software as "psychofit", so in order to clear up any confusion, the difference is as follows:


psychofit (now known as "psignifit") by Jeremy Hill

This is the software available here on , and which is referred to in the following papers:

  • Wichmann, F. A. & Hill, N. J. (2001a): The psychometric function I: fitting, sampling and goodness-of-fit. Perception and Psychophysics 63(8), 1293-1313.
  • Wichmann, F. A. & Hill, N. J. (2001b): The psychometric function II: bootstrap based confidence intervals and sampling. Perception and Psychophysics 63(8), 1314-1329.

PsychoFit by Lewis O. Harvey

Lewis Harvey's PsychoFit is not connected with this website. It is available at http://psych.colorado.edu/~lharvey/, and is described in the following papers:

  • Harvey, L. O., Jr. (1986). Efficient estimation of sensory thresholds. Behavior Research Methods, Instruments, & Computers, 18(6), 623-632.
  • Harvey, L. O., Jr. (1997). Efficient estimation of sensory thresholds with ML-PEST. Spatial Vision, 11(1), 121-128.