title: Evaluating statistical and clinical significance of intervention effects in single-case experimental designs: an SPSS method to analyze univariate data.
abstract: Single-case experimental designs are useful methods in clinical research practice to investigate individual client progress. Their proliferation might have been hampered by methodological challenges such as the difficulty applying existing statistical procedures. In this article, we describe a data-analytic method to analyze univariate (i.e., one symptom) single-case data using the common package SPSS. This method can help the clinical researcher to investigate whether an intervention works as compared with a baseline period or another intervention type, and to determine whether symptom improvement is clinically significant. First, we describe the statistical method in a conceptual way and show how it can be implemented in SPSS. Simulation studies were performed to determine the number of observation points required per intervention phase. Second, to illustrate this method and its implications, we present a case study of an adolescent with anxiety disorders treated with cognitive-behavioral therapy techniques in an outpatient psychotherapy clinic, whose symptoms were regularly assessed before each session. We provide a description of the data analyses and results of this case study. Finally, we discuss the advantages and shortcomings of the proposed method.
authors: University of Amsterdam and Research Priority Area Yield, University of Amsterdam. Electronic address: m.maric@uva.nl.
authors: Marija
authors: M
authors: Maric
authors: Academic Medical Center and Academic Center for Child and Adolescent Psychiatry, Amsterdam.
authors: Else
authors: E
authors: de Haan
authors: Academic Center for Child and Adolescent Psychiatry, Amsterdam.
authors: Sanne M
authors: SM
authors: Hogendoorn
authors: Academic Medical Center and Academic Center for Child and Adolescent Psychiatry, Amsterdam.
authors: Lidewij H
authors: LH
authors: Wolters
authors: University of Amsterdam, Cognitive Science Center Amsterdam, and Research Priority Area Yield, University of Amsterdam.
authors: Hilde M
authors: HM
authors: Huizenga
mesh_terms: D000293:Adolescent; D001008:Anxiety Disorders / Q000175:diagnosis / Q000628:therapy*; D015928:Cognitive Behavioral Therapy; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D015233:Models, Statistical; D012107:Research Design
keywords: clinical research; reliable change; single-case experimental designs; treatment efficacy; univariate data analysis