A measure of within-participant response consistency.

In this article, we introduce a measure of within-participant response consistency for use in the analysis of performance in decision-making tasks. The measure is an estimate of the correlation between the responses associated with two identical blocks of trials, the second of which has yet to be conducted. We derive a formula for the measure that can be applied to data from any two-choice decision task, including yes/no detection and two-alternative forced choice (2AFC). The estimate is easily calculated from the observed frequencies of hits, misses, false alarms, and correct rejections. We utilized data from an actual 2AFC experiment to compare estimated and observed consistency values; the estimates accounted for more than 90 % of the variability in observed consistency scores. We also discuss potential applications of the measure.