Demonstrating treatment efficacy using the single subject randomization design: A tutorial and demonstration.

Area of Science:

• Behavioral Science
• Research Methodology
• Speech-Language Pathology

Background:

• Single case research designs are valuable for studying treatment effectiveness within individuals.
• Randomization within subjects offers a rigorous approach to control for confounding variables.
• Existing literature lacks comprehensive tutorials and statistical guidance for single subject randomization designs.

Observation:

• This study details two single subject randomization designs: the randomized phase design and the randomized alternation design.
• The randomized phase design involves random assignment to treatment after a baseline phase.
• The randomized alternation design randomly allocates any session to any treatment condition.

Findings:

• A resampling test is proposed to determine the statistical significance of treatment effects.
• The test statistic involves comparing treatment session performance to baseline performance.
• The probability (P value) is derived from the distribution of all possible random allocations.

Implications:

• These designs provide a robust framework for single-subject experimental research.
• The statistical methods enable precise evaluation of interventions for individuals.
• Demonstrated utility in a case of Childhood Apraxia of Speech highlights applicability in clinical settings.