Quantifying order in response sequences

Derek Neil and John Towse


RgCalc is a computer program to aid psychological research in the area of human random generation performance, written for Windows95. It is designed to evaluate the order in a sequence of items (i.e., measure the lack of randomness), and was written by Derek Neil and John Towse. Given a set of responses, RGCalc calculates the following indices of randomisation performance:

Graphical plots of first order differences, response frequencies and repetition distances can also be selected.

A description of these measures is provided in Towse and Neil (1998), along with instructions for using the RGCalc program. This document can be obtained from either author (see below). The program is reasonably self-explanatory, but we recommend that you consult the Towse and Neil reference for details on the computation and appropriate interpretation of randomness scores.

We would welcome any comments you have about this program. You can email John Towse (j.towse@lancaster.ac.uk) or write toJohn Towse at

Department of Psychology
Fylde College
Lancaster University
Bailrigg, Lancaster, LA1 4YF
(United Kingdom)
The program can be freely distributed. We only ask that the present document is also made available or referred to, and that, where appropriate, reference is made to Towse and Neil (1998) as acknowledgement of your software use. The program below is a self-extracting archived file. A brief set of instructions is also available here.

Click here to download RGCalc

Disclaimer: In no event will John Towse, Derek Neil, or their employers be liable to you for any consequential, incidental or indirect damages arising out of the use or inability to use the software.


Towse, J.N., & Neil, D. (1998). Analyzing human random generation behavior: A review of methods used and a computer program for describing performance. Behavior Research Methods, Instruments, & Computers,30(4), 583-591.


On the second page of the article, Evans' RNG index (Equation 4) is described as

RNG = sum (n(ij)log(n(ij))) / sum (n(ij)log(n(i))).

whereas the RNG formula should be

RNG = sum (n(ij)log(n(ij))) / sum (n(i)log(n(i))).

That is, one divides by the sum of the products of response frequencies and log (response frequencies), not the product of the response pairs and log (response frequencies). RGCalc implements the correct formula and we apologise for the typographical error in the article.