Single-case experimental design

A rigorous research methodology that evaluates intervention effects by systematically alternating between baseline and treatment conditions within individual participants, using each person as their own control. Common variants include AB, ABA, ABAB, and multiple-baseline designs. Single-case experimental designs are particularly valuable in accessibility research where participant pools are small due to the specificity of disability populations, as they can achieve statistical significance with as few as one participant through repeated within-subject measurements and visual or statistical analysis of phase changes.