A comparative usability evaluation was performed using various subjective evaluation methods, including Mobile Phone Usability Questionnaire (MPUQ). Further, decision-making models using Analytic Hierarchy Process (AHP) and multiple linear regression were developed and applied. Although the mean rankings of the four phones were not significantly different across the evaluation methods, there were variations across the methods in terms of the number of rank orderings, preference proportions, and methods to select their initial preference. Thus, this study provided a useful insight into how users make different decisions through different evaluation methods. Also, the result showed that answering a usability questionnaire affected a user’s decision-making process for comparative evaluation.
Practitioner’s Take Away
The following important usability dimensions and items for mobile phone usability were based on MPUQ (Mobile Phone Usability Questionnaire) results using several usability evaluation methods(Ryu & Smith-Jackson, 2006):
- EC (Efficiency and Control) for Minimalists
- TTMP (Typical Task for Mobile Phones) for Voice/Text Fanatics
Thus, if usability practitioners want to employ a short list of questions to compare mobile phones for each user group, the questions from EC (9 questions) and TTMP (7 questions) of MPUQ could be selected as appropriate.
Also, the activity of answering a usability questionnaire has the following effects:
- improves users’ ability to provide specific design recommendations (Kirakowski, 1996)
- affects users’ decision-making process for comparative evaluation.
The results and outcomes of this paper were restricted to two major mobile user groups, Minimalists and Voice/Text Fanatics.