Teach or Design? How Older Adults' Use of Ticket Vending Machines Could Be More Effective
Michael Sengpiel · 2016 · ACM Transactions on Accessible Computing · doi:10.1145/2935619
Summary
This study addresses the "teach or design" debate in accessible technology by comparing two interventions to improve older adults' use of ticket vending machines (TVMs). The research recruited 62 older adults (mean age 68) and 62 younger adults (mean age 25) to test three conditions: the original Berlin public transit TVM, a 2.5-minute instructional video teaching six core interaction concepts, and a wizard-style redesign using four task-oriented questions (Who is traveling? Where? How long? How many tickets?). The original TVM revealed significant age differences: younger participants achieved 84% effectiveness while older participants managed only 52%. The study measured effectiveness (task completion), efficiency (steps and time), and satisfaction using validated instruments alongside control variables including computer literacy, control beliefs about technology, attitudes, and anxiety. The methodology involved 11 ticket purchasing tasks of varying complexity, from simple single tickets to multi-person day passes with specific route requirements.
Key findings
Both interventions dramatically improved older adults' effectiveness. The instructional video raised older adults' effectiveness from 52% to 80%, while the wizard design achieved 89%—nearly matching younger participants' 84% baseline. Crucially, the wizard eliminated statistically significant effectiveness differences between age groups entirely, achieving the universal usability goal where all users can succeed regardless of age. However, neither intervention closed the time efficiency gap: older adults consistently took 1.5-2 times longer than younger adults across all conditions, consistent with research on age-related processing speed. The video improved efficiency in interaction steps but not time, while the wizard traded step efficiency for reliability—requiring more steps but producing consistent success. Satisfaction was high across all conditions and did not differentiate between groups, though the wizard yielded significantly higher satisfaction among older participants than the control condition. Computer literacy did not differ between experimental conditions, confirming that usability improvements were due to the interventions rather than participant characteristics.
Relevance
This research has direct implications for designing accessible public kiosks, self-service terminals, and walk-up-and-use systems. The findings suggest organizations should combine both approaches: wizard-style interfaces for reliability on rarely-used systems, and brief instructional videos for frequently-used systems where learning transfers across visits. The study validates that age-related usability gaps can be eliminated through thoughtful design without requiring users to have prior technology experience. However, practitioners should not expect to close time efficiency gaps—older users will likely always need more time, which has implications for queue management and time-limited interactions. The concept of a "universal ticket vending machine" integrating with mobile devices points toward future designs where complex selection happens on personal devices and the public terminal handles only printing/payment.
Tags: older adults · public access systems · universal usability · computer literacy · kiosk design · training