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Journal of Behavioral Education





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Determining how best to meet the needs of learners with Down syndrome requires an approach to intervention delivered at some level of intensity. How treatment intensity affects learner acquisition, maintenance, and generalization of skills can help optimize the efficiency and cost effectiveness of interventions. There is a growing body of research on the effects of treatment intensity but almost no systematic study of it with children with Down syndrome, providing little guidance about how to approach the study of intensity. In two preliminary studies we manipulated different aspects of the dose of treatment intensity and measured effects on skill acquisition using single-subject experimental designs. Intensity varied in terms of number of opportunities per session, session duration, and spacing of opportunities (inter-stimulus interval). Matched responses within a skill area were randomly assigned to a level of intensity and acquisition was compared. Results reveal lessons about what aspects of intensity to manipulate and how, selecting experimental designs, measuring multiple outcomes, and the influence of learner characteristics. These lessons highlight directions for future approaches to tease apart the relative contributions of different aspects of intensity on skill acquisition and determine the most effective intensity of early intervention for children with Down syndrome.


This is a post-peer-review, pre-copyedit version of an article published in Journal of Behavioral Education. The final authenticated version is available online at:

Citation of this paper:

Neil, N., & Jones, E. A. (2015). Studying treatment intensity: Lessons from two preliminary studies. Journal of Behavioral Education, 24(1), 51-73. doi: 10.1007/s10864-014-9208-6

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