Semi-parametric regression as a tool for assessing moderation: an analysis of the Fast Track intervention

  • E. Michael Foster
  • Stephanie Watkins


When assessing the impact of a family or youth intervention, program evaluators often consider whether and how baseline characteristics moderate the effect of treatment. Parametric and non-parametric approaches are both possible, but each has limitations. In this article, we argue for and illustrate the use of semi-parametric methods. A hybrid of parametric and non-parametric approaches, semi-parametric modeling techniques combine the strengths of each approach. This article demonstrates how this approach can be used to evaluate whether an intervention effect was larger for those with most serious problems at baseline. Using data from the Fast Track project—a comprehensive intervention designed to prevent serious conduct problems among children at high risk—we investigated the moderating effect of two key baseline characteristics: parent-reported and teacher-reported problem behavior. Our analyses do not demonstrate a significant moderation of the intervention effect.


Fast Track Moderation Semi-parametric Differencing 



This work was supported by National Institute of Mental Health (NIMH) grants R18 MH48043, R18 MH50951, R18 MH50952, and R18 MH50953. The Center for Substance Abuse Prevention and the National Institute on Drug Abuse also has provided support for Fast Track through a memorandum of agreement with the NIMH. This work was also supported in part by Department of Education grant S184U30002 and NIMH grants K05MH00797 and K05MH01027. The economic analysis of the Fast Track project is supported through R01MH62988. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute On Drug Abuse or the National Institutes of Health.


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© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Department of Maternal and Child Health, School of Public HealthUniversity of North Carolina at Chapel HillChapel HillUSA
  2. 2.Department of Epidemiology, School of Public HealthUniversity of North Carolina at Chapel HillChapel HillUSA

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