A usability comparison of three alternative message formats for an SMS banking service

The study reported here compares the usability of three types of message input format: Abbreviations, Numbers and Free-Form as alternatives for a Pull SMS banking service. Participants (N=74) used all three formats to carry out three banking transactions in a repeated measures experiment. The Abbreviations and Numbers versions of the service performed to generally equal levels in all metrics. Free-Form performed the worst as participants took significantly longer to complete tasks and it received significantly lower overall questionnaire and quality scores for satisfaction. The older age group found all three versions in general to be less usable than the younger age group. They took longer on the tasks, had lower completion rates and they also gave each version a lower overall mean satisfaction score.