Within-Subject Design

An experimental research design where each participant is exposed to all conditions being compared, rather than assigning different participants to different conditions. In accessibility user studies, within-subject designs are common because they require fewer participants — an important advantage given the difficulty of recruiting users with specific disabilities. Each participant serves as their own control, reducing the impact of individual differences on results. Potential drawbacks include learning effects (participants may perform better in later conditions due to practice) and fatigue effects, which are typically mitigated through counterbalancing the order of conditions across participants using methods like the Latin Square design.