Small n Designs

1. General features of small n research (sometimes called single-case research)

A. Emphasis on individual performance and not on average group performance

B. Withholding treatment for long periods is avoided

C. Fewer participants are needed.

2. Most small n research is conducted from an applied behavior analysis perspective. Its characteristics include:

A. Practical nature of the research problem
B. Behavioral focus of the research
C. Many observations on the dependent variable
D. Self-examining nature of the research process
E. Results interpreted in terms of practical impact (i.e., clinical significance) and not statistical significance

3. Measurement issues in applied behavior analytic research

A. Defining, observing, and recording
B. Functions of baselines
C. Baseline variability and trends

4. AB design

(Thumbsucking frequency in a 9 year-old boy during television viewing. Baseline consisted of 21 observations per week. The horizontal axis is measured in weeks. These are the first two panels of a study conducted by Ross. Source: Kazdin).

5. Reversal design (ABA or ABAB, etc.) (Examples)

6. Multiple baseline designs (Examples)

A. Across subjects
B. Across behaviors
C. Across situations

7. External validity concerns in small n designs