The effect of economic condition on the relation between responding and overall rate of reinforcement has been an area of recent interest in operant research. The present research was conducted to determine whether the manipulation of the economic condition, by the systematic manipulation of the provision of substitute food, has an effect on this relation and whether open- and closed-economies represent two opposing alternatives or two parametric extremes along- a continuum. The results of two experiments conducted with pigeons using variable-interval and fixed-ratio schedules of reinforcement suggest that the manipulation of economic condition has a controlling effect on the relation between responding and overall rate of reinforcement, that open- and closed- economies are likely to represent points along- a continuum rather than all-or-none conditions, and that the differences in the response-to- reinforcement relation between open- and closed-economies are likely due to an interaction of incentive and regulatory effects. Additionally, specific methodological considerations for further research in this area are suggested.