Comparing Single Case Design Overlap-Based Effect Size Metrics From Studies Examining Speech Generating Device Interventions.
Meaningfully synthesizing single case experimental data from intervention studies comprised of individuals with low incidence conditions and generating effect size estimates remains challenging. Seven effect size metrics were compared for single case design (SCD) data focused on teaching speech generating device use to individuals with intellectual and developmental disabilities (IDD) with moderate to profound levels of impairment. The effect size metrics included percent of data points exceeding the median (PEM), percent of nonoverlapping data (PND), improvement rate difference (IRD), percent of all nonoverlapping data (PAND), Phi, nonoverlap of all pairs (NAP), and Tau(novlap). Results showed that among the seven effect size metrics, PAND, Phi, IRD, and PND were more effective in quantifying intervention effects for the data sample (N = 285 phase or condition contrasts). Results are discussed with respect to issues concerning extracting and calculating effect sizes, visual analysis, and SCD intervention research in IDD.
Mo Chen, University of Minnesota, Minneapolis, MN;
Mo
M
Chen
Jolene K. Hyppa-Martin, University of Minnesota, Minneapolis, MN and University of Minnesota Duluth, Duluth, MN;
Jolene K
JK
Hyppa-Martin
Joe E. Reichle, University of Minnesota, Minneapolis, MN; and.
Joe E
JE
Reichle
Frank J. Symons, University of Minnesota, Minneapolis, MN.
Frank J
FJ
Symons
D003143:Communication Devices for People with Disabilities; D003627:Data Interpretation, Statistical; D002658:Developmental Disabilities / Q000534:rehabilitation*; D006801:Humans; D008607:Intellectual Disability / Q000534:rehabilitation*; D017063:Outcome Assessment, Health Care / Q000592:standards*; D012107:Research Design / Q000592:standards*
effect size metric; evidence-based practices; intellectual and developmental disabilities; single case design; speech generating devices