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. (Contains 1 table.)