Usability Evaluation in Mobile Operating Systems for Touchscreen Smartphones

1. Usability Evaluation in Mobile Operating Systems for Touchscreen Smartphones Olli Rahikka Espoo, 18.4.2012 Supervisor and instructor: Adj. Prof. Timo O. Korhonen

2. Contents • Introduction • Research questions • User-centered design • Usability factors in touchscreens • Usability evaluation methods • Usability evaluations and results • Conclusions • Topics for future studies

3. Introduction • Smartphones have become very popular • Smartphone shipments have surpassed feature phone shipments • Most smartphones have a touchscreen • Manufacturers are focusing to usability • Similar features in phones from different manufacturers • Usability must be evaluated to be able to improve it

5. Research questions • How are user-centered design methodologies and processes usually applied in the usability studies of touchscreen devices? • What are the most important usability factors in touchscreens and how are they usually addressed? • How to select the usability evaluation method for touchscreen based mobile operating systems? • What usability issues are present in the user interface of the current application store of the "bada" operating system? • What usability issues are present in the current NFC function of the "bada" operating system?

6. User-centered design • User-centered design process • Usability engineering lifecycle • Logical User Centered Interaction Design • The process of human-centered interactive systems design • Evaluation and iteration are key activities

7. Usability factors in touchscreens • Size of the screen • Precision • Responsiveness • Virtual keypad • Screen coverage • Direct activation

8. Usability evaluation methods

9. Selection of the usability evaluation method • Available time, money and human resources affect to the selection

10. Usability evaluation 1 • Heuristic evaluation of Samsung Apps • Purpose • find as many usability issues as possible • Interface was studied three times with the used heuristics in mind • Found issues were written down • Severity of the issues was determined • Improvement suggestions were presented

11. Results from usability evaluation 1 • 12 usability issues were found • 1 catastrophe, 3 major, 4 minor, 4 cosmetic • Example:

12. Usability evaluation 2 • Usability test of Near Field Communication function • Purpose • find out the usability issues in both the NFC application’s user interface and in the required user actions to read and write NFC tags • 15 test participants • 6 different tasks, questionnaire after each task • Debriefing session after the test

13. Results from usability evaluation 2 • 7 usability issues were found • 3 high priority, 2 medium priority, 2 low priority • Participants learned to use the NFC application after 3 tasks • Test times were greatly reduced • Test participants were satisfied with the user experience

14. Conclusions • Mobile operating systems differ from desktop operating systems • Differences have to be taken into account when desiging user interfaces • Selecting the correct usability evaluation method is not always easy

15. Conclusions • Heuristic evaluation and usability testing are suitable methods for evaluating the usability in mobile operating systems • More usability issues would probably have been found if several usability evaluators had studied the interface in heuristic evaluation • Using at least some context specific heuristics in the evaluation turned out to be good choice • Usability testing gives valuable information from the users of the product

16. Topics for future studies • Evaluate the whole user experience between different mobile operating systems • Evaluate and compare the usability of the new touchpanel technologies