Within- and across-session increases in work requirement do not produce similar response output

Demand curve fitting is a method of data analysis for interpreting reinforcer consumption. These methods were established and validated by examining increases in unit price (UP) across sessions. An alternative experimental preparation is the progressive-ratio (PR) schedule in which schedule requirements increase within a session. Although PR schedules provide an efficient alternative to traditional evaluations of UP, using demand curves to interpret data obtained via PR schedules has not been systematically evaluated in applied contexts. In this study, the experimenters compared demand curves constructed based on across- and within-session increases in UP and evaluated correspondence between the two methods. Results indicated poor correspondence between demand curves constructed with the two methods. Furthermore, within-session measures of responding suggest that higher rates of problem behavior and longer durations of postreinforcement pauses were more likely under PR schedules than fixed-ratio schedules. Results are discussed in terms of implications for clinical application.