Analyzing Correlations Between Refined Comfort Score, Usability, and Performance in Assistive Technology

Assistive technology (AT) enhances accessibility and usability for persons with disabilities. Prior research identifies the disability paradox, where persons with disabilities rate assistive systems more favorably despite lower objective performance. However, the extent to which subjective comfort influences usability and task performance remains unclear. This study applies a standardized approach to quantifying comfort through the Refined Comfort Score (RCS), which aggregates thirteen items from the Device Assessment Questionnaire to assess overall user comfort. By analyzing RCS, perceived usability from the System Usability Scale, and objective performance indicators such as task completion and task duration, this study examines how comfort and usability interact across user groups. The findings reveal that higher RCS strongly correlates with greater usability perception in both groups, yet its influence on task performance differs. Among persons with disabilities, higher RCS significantly correlates with increased task completion, whereas this relationship is absent for persons without disabilities. Feature importance analysis further highlights that comfort is the dominant determinant of task completion for persons with disabilities, while usability plays a greater role for persons without disabilities. These results suggest that comfort is a key factor in AT effectiveness, particularly for persons with disabilities. This study emphasizes the need to integrate comfort metrics into AT design and evaluation within human-computer interaction, ensuring usability improvements align with diverse user needs.