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IES Grant

Title: Further Development of Effect Size Estimators for Single-case Designs: Extensions to Trend and Diverse Outcome Metrics
Center: NCER Year: 2015
Principal Investigator: Hedges, Larry Awardee: Northwestern University
Program: Statistical and Research Methodology in Education      [Program Details]
Award Period: 3 years (7/1/156/30/18) Award Amount: $899,884
Type: Methodological Innovation Award Number: R305D170041

Previous Award Number: R305D150041
Previous Institution: University of California, Merced
Previous PI: William Shadish

The purpose of this project is to extend previous work done through an IES-funded grant (A d-Estimator for Single Case Designs) by developing effect size measures that can account for trends when there is a repeated assessment of an outcome over time and that can be used with outcome variables measured as count or rate data, which are common in single-case research. In addition, the research team will develop approaches to gauge the sensitivity of a planned study to detect effects and software with which applied researchers can obtain such an estimate. They will extend their existing user-friendly software that computes the current version of their effect size metric by adding the capacity to compute estimates of the new effect size and compute the sensitivity of a design to detect an effect.

After some analytical work to develop the new effect size measures, the research team will use simulation studies to investigate the performance of the measures under a range of conditions typically found in single-case designs. Through additional analytical work, the research team will ascertain the statistical properties of the effect size measures. The team will then conduct more simulation studies, which focus on evaluating the necessary attributes for single-case designs to be able to detect the effects. As these measures clear the testing phase, the research team will program them into their current SPSS software for computing the effect size estimates from the previous grant work. Other products of this grant will include conference presentations and peer-reviewed journal articles reporting on the methodological work and the application of it to single-case research.

Related IES Funded Project: A d-Estimator for Single Case Designs (R305D100046)


Journal article, monograph, or newsletter

Shadish, W.R., Zelinsky, N.A., Vevea, J.L., and Kratochwill, T.R. (2016). A Survey of Publication Practices of Single-Case Design Researchers When Treatments Have Small or Large Effects. Journal of Applied Behavior Analysis, 49(3), 656–673.