A control procedure that is used to stop rapid switching between alternatives on concurrent schedules of reinforcement. The COD contingency stipulates that responses do not have an effect immediately following a change from one schedule to another. After switching to a new alternative, a brief time is required before a response is reinforced. For example, if an organism has just changed to an alternative schedule that is ready to deliver reinforcement, there is a brief delay before a response is effective. As soon as the delay has elapsed, a response is reinforced. The COD contingency operates in both directions whenever a change is made from one alternative to another.