Prevalence of multiply controlled problem behavior.

We examined articles in the Journal of Applied Behavior Analysis in which results of functional analyses indicated that problem behavior was maintained by multiple sources of reinforcement. Data for 88 (16.9%) of 521 subjects reported in 168 studies met the criteria for multiple control. Data for 11 subjects (2.1%) involved a single response topography, whereas data for 77 subjects involved multiple, collapsed response topographies (14.8% of the total [521 cases] or 87.5% of the multiple control cases), suggesting that when multiple control is observed, it often may be a by-product of response aggregation during assessment.