The article discusses the distinction between discriminative and motivational functions of stimuli in operant behavior. A discriminative stimulus (SD) is a stimulus that increases the frequency of a particular response because it has been correlated with an increase in the frequency of that response being followed by reinforcement. However, there are situations where a stimulus change functions more like an establishing operation than a discriminative stimulus. An establishing operation is a change in the environment that alters the effectiveness of some object or event as reinforcement and simultaneously alters the momentary frequency of the behavior that has been followed by that reinforcement. The term "establishing operation" is suggested as a general term for these two effects. The article also introduces the concept of an "establishing stimulus," which is a stimulus that functions as a discriminative stimulus for one response but as an establishing operation for another. The article provides examples of both human and animal situations to illustrate these concepts. It argues that the term "establishing operation" is more appropriate than "deprivation" for describing the effects of certain stimuli on behavior. The article also discusses alternative solutions to the terminological problem, such as using larger units of behavior or conditional conditioned reinforcement. However, the author concludes that the term "establishing operation" is the most appropriate and useful for describing the effects of certain stimuli on behavior.The article discusses the distinction between discriminative and motivational functions of stimuli in operant behavior. A discriminative stimulus (SD) is a stimulus that increases the frequency of a particular response because it has been correlated with an increase in the frequency of that response being followed by reinforcement. However, there are situations where a stimulus change functions more like an establishing operation than a discriminative stimulus. An establishing operation is a change in the environment that alters the effectiveness of some object or event as reinforcement and simultaneously alters the momentary frequency of the behavior that has been followed by that reinforcement. The term "establishing operation" is suggested as a general term for these two effects. The article also introduces the concept of an "establishing stimulus," which is a stimulus that functions as a discriminative stimulus for one response but as an establishing operation for another. The article provides examples of both human and animal situations to illustrate these concepts. It argues that the term "establishing operation" is more appropriate than "deprivation" for describing the effects of certain stimuli on behavior. The article also discusses alternative solutions to the terminological problem, such as using larger units of behavior or conditional conditioned reinforcement. However, the author concludes that the term "establishing operation" is the most appropriate and useful for describing the effects of certain stimuli on behavior.