Measuring mobile device proficiency: a cross-sectional validation of the shortened japanese version of the mobile device proficiency questionnaire

• Developed and validated two shortened Japanese MDPQ versions using item response theory. • MDPQ-J14 and MDPQ-J20OA provide efficient, age-appropriate assessment of device proficiency. • Shortened tools reduce respondent burden while maintaining reliability and validity. • Cultural adaptation led to exclusion of less relevant subcategories for Japanese users. Mobile devices enhance the independence and quality of life of older adults by supporting communication, information access, and daily functioning. However, many older individuals struggle to effectively use such technologies. Accurate assessment of mobile device proficiency is essential for tailoring support and promoting digital inclusion in the aging population. Although the Japanese version of the Mobile Device Proficiency Questionnaire (MDPQ-J) has demonstrated strong validity, its 46-item format imposes a burden on respondents and limits its utility in field settings. This study aimed to develop and validate shortened versions of the MDPQ-J using item response theory to provide efficient and psychometrically sound tools for assessing mobile device proficiency in older Japanese adults. A total of 229 Japanese participants, including 108 older adults (aged >65years), completed the full 46-item MDPQ-J. Rasch analysis and item response theory were applied to evaluate dimensionality, item fit, and local independence. A reduction in the number of items in the MDPQ-J was appropriate, and two shortened versions were developed: MDPQ-J14 for the general population and MDPQ-J20OA for older adults. Items were selected based on model fit, local independence, and discrimination parameters. In MDPQ-J14, “Use video-messaging apps” showed the highest discrimination, whereas in MDPQ-J20OA, “Copy and paste text using the touchscreen” demonstrated the strongest item discrimination. The MDPQ-J14 and MDPQ-J20OA are efficient, valid, and culturally appropriate tools for assessing mobile device proficiency. Their brevity and flexibility make them suitable for wide application in research, education, and gerontechnology interventions in aging societies.