Cohen's Kappa

A statistical measure of inter-rater reliability that accounts for agreement occurring by chance, used to assess the consistency between two or more raters coding qualitative data. Values range from -1 to 1, where 1 indicates perfect agreement, 0 indicates agreement no better than chance, and negative values indicate less than chance agreement. In accessibility research, Cohen's Kappa is commonly used to validate the reliability of qualitative coding in studies involving thematic analysis of user experiences, content analysis of accessibility features, and evaluation of assistive technology interfaces.