Design and Psychometric Evaluation of an American Sign Language Translation of the System Usability Scale.

In usability studies, designers and researchers frequently use subjective questions to evaluate participants' impression of the usability of some product. The System Usability Scale (SUS) is a popular standardized questionnaire consisting of ten English statements about the usability of a product, to which participants indicate their agreement on a five-point scale. Many deaf adults in the U.S. have lower levels of English reading literacy, but there are currently no standardized questionnaires similar to SUS for Deaf and Hard-of-Hearing (DHH) users who are fluent in American Sign Language (ASL). To facilitate the inclusion of such users in studies, we created an ASL translation of SUS following accepted methods of survey translation: using a bilingual team including native ASL signers who are members of the Deaf community, along with back-translation evaluation to determine whether the meaning of the original was preserved. To validate whether key psychometric properties were preserved during translation, we deployed the ASL instrument in a study with 30 DHH participants. By comparing the results to users? responses to another measurement instrument, along with scores from 10 additional DHH participants responding to the original English SUS, we verified the criterion validity and internal reliability of the new "ASL-SUS." We are disseminating the translated instrument to promote the inclusion of DHH users in HCI research studies or in usability testing of consumer products.