Ratio strain versus breaking point are two terms that I have found are often mixed up, so let’s clarify. Ratio strain has to do with thinning reinforcement schedules. Schedules of reinforcement should absolutely be thinned, but they have to be thinned gradually to avoid ratio strain, which describes what happens when we thin too abruptly. That can be increases in challenging behaviors or new behavior surfacing, like non-compliance, avoidance, and aggression. This type of response is the direct result of extreme increases in ratio requirements when we move from what we call denser schedules (that’s a lot of reinforcement) to thinner schedules (less reinforcement). But, when you thin gradually, that’s less jarring, and the client gradually experiences that thinning change, and therefore is less likely to exhibit some of these increases or new problem behaviors.
In contrast to breaking point, which has to do specifically with the progressive schedule of reinforcement or progressive schedule reinforcer assessment, that’s the primary measure of interest; it’s what we seek with the schedule because we want to find out how far the reinforcer is going to go. We systematically thin each successive reinforcement opportunity, completely independent of the client’s behavior, and keep doing that until the client stops responding. That moment is what we call the breaking point. It helps to assess the strength of the reinforcer; essentially, how far can that reinforcer go? This is based on the assumption that there is a direct relationship between how hard we work and the potency of the specific reinforcer, which, again, is assessed by looking at the breaking point, the “how far” that reinforcement can go or how far it went.