Single Case Experimental Design

A research methodology in which individual participants serve as their own control, with repeated measurements taken during baseline and intervention phases to evaluate the effect of a treatment or intervention. This approach is particularly valuable in accessibility and disability research where the heterogeneity of participant populations makes large group studies difficult — no two individuals with autism or other conditions present identically. Common designs include AB (baseline then intervention), ABA (with withdrawal), and multiple-baseline approaches. The method allows researchers to observe individual change trajectories and tailor interventions to each participant.