Convergence: Connecting Levels of Analysis in Psychological Science
 In the past, our field harbored distinct, and often competing, schools of thought that tackled different problems and produced findings that often appeared to diverge. Today, investigators attack shared problems at complementary levels of analysis and produce results that converge. Studies of people in a social world; mental systems of cognition and emotion; and biological mechanisms of the genome and the nervous system interconnect and yield an integrated psychological science. The APS 23rd Annual Convention displays, and celebrates, these advances in our field.

Cross-cutting Invited Symposium

Advances and Applications in Single Case Design

Saturday, May 26, 2012, 10:30 AM - 11:50 AM
Chicago Ballroom VIII

Ellen L. Hamaker Chair: Ellen L. Hamaker
Utrecht University, The Netherlands
Howard N. Garb Chair: Howard N. Garb
Wilford Hall Surgical Ambulatory Center

Single-case research provides a unique opportunity for psychologists to investigate whether a specific individual has benefitted from an intervention or treatment. In this joint symposium of the Clinical and Methodology Tracks, the strengths and weaknesses of single-case experiments will be addressed. Examples of single-case studies are presented, and ideas for improving the rigor of this approach will be discussed.

Continuing Education: 1.5 APA Credits

Learning Objectives

This Symposium is designed to help you:

1. Describe the strengths and weaknesses of single-case studies.

2. Evaluate the rigor a single-case study.

3. Design an intensive study of an individual (e.g., a client).

Continuing education for psychologists is sponsored by the Psychology Department at the Wilford Hall Ambulatory Surgical Center (WHASC). The Psychology Department at WHASC is approved by the American Psychological Association to sponsor continuing education for psychologists. WHASC maintains responsibility for this program and its content. Point of contact for the CE Program is Howard Garb. He can be reached at, or 210.671.4084.

Matthew K. Nock

Doing More With Less: (Re)focusing Psychology on the Study of Change Within Individuals
Matthew K. Nock
Harvard University
Since the earliest days of psychology, researchers have studied individuals intensively over time in order to learn about human behavior. However, in recent years there has been a much greater focus on the use of cross-sectional between groups’ designs. This presentation proposes a refocusing on the intensive study of individuals over time and uses several recent single-case studies as examples of such an approach.

Thomas R. Kratochwill

Distinguishing Design and Evidence: The What Works Clearinghouse Single-Case Research Standards
Thomas R. Kratochwill
University of Wisconsin-Madison
This presentation will provide an overview of the What Works Clearinghouse Single-Case Design (SCD) Standards. The Standards are divided into Design Standards and Evidence Standards, which are sequentially applied to review of research studies that incorporate SCDs. The Design Standards focus on the methodological soundness of SCDs, and allow assignment to the categories of Meets Standards, Meets Standards with Reservations, and Does Not Meet Standards to each study. The Evidence Standards focus on the strength of the reported evidence, whereby the outcome measures from all studies that meet the Design Standards (with or without reservations) are examined by reviewers trained in visual analysis and categorized as demonstrating Strong Evidence, Moderate Evidence, or No Evidence. Issues that the Standards do not address are presented for future consideration. Implications for future SCD research are also presented.

Michael Nash

The Single-Case Outcome Study
Michael Nash
University of Tennessee, Knoxville
In the single-case study, just as with group designs, there are three approaches to whether the patient’s observed clinical improvement is notable or important: a) Testing the observed improvement against the null hypothesis (e.g., SMA, Borckardt et al, 2008), b) Testing it against the criterion measure’s norms (e.g., RCI, Jacobson et al, 1999), and c) Testing the meaningfulness of the improvement (i.e., Kazdin, 2006). These approaches deliver inferential yields that are to a degree conceptually distinct. In this paper, we focus primarily on testing the null hypothesis. Serial dependence in single-case design poses formidable barriers to null hypothesis testing, but we explain how simulation modeling enables us to ascertain the likelihood that the observed clinical improvement would occur under random conditions. We use case examples to illustrate how null hypothesis, criterion norms, and meaningfulness approaches are used together to give a robust depiction of clinical change and its importance.

Patrick M. Onghena

The Curious Case of Single-Case Research: Causal Inference From Randomized Single-Case Experiments
Patrick M. Onghena
Katholieke Universiteit Leuven, Belgium
A single-case study can be a true experiment if there are repeated measures and there is a deliberate manipulation of at least one independent variable. The addition of a random assignment schedule in a single-case experiment can offer statistical control of time-related confounding variables. Furthermore, such a schedule provides the basis for a valid statistical test, the so-called randomization test. In this contribution, it is argued that statistical power can be gained by replicating the experiments simultaneously (as in multiple baseline designs across participants) or sequentially (mere consecutive experiments, which can be combined in a meta-analysis). Finally, we will reflect on the meaning of the resulting individual or combined p-value, and on the necessity to complement the p-values by indicators of effect size.

David H. Barlow

David H. Barlow (Discussant)
Boston University

Subject Area: Methodology

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