Single-blind AB Design

The single-blind AB design is a single-subject experimental design that combines the two-phase AB structure — a baseline phase (A) followed by an intervention phase (B) — with assessor or observer masking. The individual collecting or rating outcome data is kept unaware of which phase is being measured, preventing knowledge of treatment status from biasing behavioral observations or ratings. The design improves on the standard AB design by reducing detection bias while retaining the practical and ethical advantages of single-subject methodology.