Single-blind single-subject experimental design

A single-blind single-subject experimental design (SB-SSED) applies a single-blind protocol to an N-of-1 experiment: one individual participant is studied intensively across alternating or sequential phases, and either the participant or the assessor — but not both — is kept unaware of the current treatment condition. This design combines the idiographic power of single-subject methodology with a structured blinding control to reduce performance or assessment bias, and is common in applied behavior analysis, clinical psychology, and rehabilitation research.