The convergent, discriminant, and incremental validity of the Discounting Inventory compared to the traditional discounting measures

Abstract

The Discounting Inventory was developed to provide researchers and practitioners with a standardized tool to asses individual differences in delay, probabilistic, effort and social discounting, all related to behavioral impulsivity. Convergent and discriminant validity of the Discounting Inventory was evaluated by comparing its associations with external variables to those obtained using standardized discounting measures with the same external variables. A sample of 347 volunteers was examined. The first questionnaire completed by all participants was the Discounting Inventory. Individuals also completed the traditional discounting measure using pairs of hypothetical choices. The external measures included the Sensation Seeking Scale, Barratt Impulsiveness Scale, Eysenck Impulsivity Venturesomeness Empathy Questionnaire, Eysenck Personality Questionnaire-Revised, and Temperament and Character Inventory. The results revealed that although almost all correlations were significant for both the Discounting Inventory and the traditional discounting measures, most of the correlations between external variables and the Discounting Inventory were significantly higher than those between external variables and traditional discounting measures. However, both discounting measures were most strongly correlated with external measures of impulsivity, which is not surprising given the fact that discounting is seen as a behavioral impulsivity. Finally, most relationships between the Discounting Inventory and external variables were incrementally valid over the traditional discounting measures. The Discounting Inventory can help to diagnose problems with behavioral impulsivity.