An Investigation on Mobile Phone Users’ Performance of Using Chinese Input Systems

1. An Investigation on Mobile Phone Users’ Performance of Using Chinese Input Systems Zhenqing WU Hongbo MENG Xiaoda LU Yongkang GUO Yao DING

2. The objective is to… • To develop a statistically reliable analysis on possible factors that may have influence on the usability of Chinese input on mobile phones.

3. We are interested in… • Usability • Average typing speed • Error rate • User satisfaction

4. Cause-and-effect diagram Measurement User Environment Text Age Temperature Difficulty Surveyor Punctuation Concentration Lightness Mandarin level Background noise Length Usability Touch-screen Key size Pinyin Layout Hand-writing Button Key shape Stroke Screen size Keypad Input method Input device

5. Control variables • Input methods • Pinyin • Stroke • Input devices • Touch-screen • Button • Keypad layout • Numeric keypad • Full keypad

6. Constant variables • Associating input • Fonts • Screen contrast • Screen brightness • Environment factors

7. Nuisance variables • Differences among subjects • Mandarin level • Chinese input habit • Concentration • Differences among testing materials –- Testing material design guidelines • 不是成句的词组形式，否则输入法处理过于简易； • 句式不可过于复杂，避免因此而导致的测试者之间的噪音； • 句子长度控制在20字左右为佳； • 句子之间的标点应该保持一致，避免因为标点转换而造成的时间差异。

8. Testing materials • 曾经有一段很美好的爱情在我面前，但我却没有珍惜。 • 无偿献血是公民应尽的义务，挽救生命是你我的职责。 • 足球周刊是一份十分不错的杂志，只是售价常常太贵。 • 今晚六点在大礼堂召开总结大会，请代表们准时出席。 • 唐代是诗歌最光辉的顶点，涌现了一大批杰出的诗人。 • 我在一楼第二候车室等你，火车晚上九点就要出发了。 • 最近做事丢三落四，出门的时候竟然忘了带上电源线。 • 这次的实验大家花了很大的心血，确保实验的完整性。

9. Apparatus

10. Method • 6*6 Latin square design

11. Pre-/Post-questionnaire

12. Performance measurement • Average typing speed • Stop watch • Error rate • Number of clicking “backspace”

13. Data Processing Part

14. Latin Square Design • To eliminate the two nuisance sources of variability: • The test material used • The different subject chosen for the test • Since there are six treatments, six subjects are chosen and they are tested on six different test materials.

15. Latin Square Design • Model: yi=µ+αi+βj+τk+ξijk

16. Latin Square Design

17. Latin Square Design • Data for input time and input speed are collected as follows:

18. Latin Square Design • Input time: • Significantly different among treatments • Insignificant difference among subjects and materials

19. Latin Square Design • Input accuracy • Significantly different among subjects • Insignificant difference among treatments and materials

20. Analysis on different treatments • At first a 23 full factorial design • Swapped to separately process pinyin input data and stroke input data • No possible combination of full keyboard and stroke • People stick with one preference among pinyin input method and stroke input method

21. Analysis-Pinyin • 22 full factorial design • Deal with different combinations of subjects and materials as replicates of each design (No significant effect is shown in the Latin square analysis)

22. Analysis-Pinyin

23. Analysis-Pinyin

24. Analysis-Pinyin

25. Analysis-Pinyin • Effect of factors • Numeric keyboard would increase speed • Button keys would increase speed • Best Combination: • Numeric keyboard + Button keys • Worst Combination: • Full keyboard + Touch screen

26. Analysis-Stroke • Two-sample t-test • P-Value=0.672>α • No significant difference

27. Flaws of Results • Consideration of user habits • Sample size

28. Missing value full factorial design

29. For the speed Subject 1 Pinyin is very helpful

30. For the speed(without interaction) Most users Need more factors to do future experiment

31. For the speed(with interaction) Most users Need more factors to do future experiment

32. For the accuracy Subject 1 input method and key type(touch or button)

33. For the accuracy Most users whether the input method is Pinyin or Stroke and whether the key layout is full or numberic keyboard are very critical.

34. Conclusion • For the input speed, each people may have different significant factors, for the most users, it seems like that we have to include other factors to give further conclusion. • For the input accuracy, people may have different significant factors just like their impact on input speed, however, for the most users, we can conclude, that Pinyin and Numeric keypad are very helpfull to reduce the error rate.

35. User Satisfaction • Content • Basic information of subjects • Indices rating from 1 to 7 • Shortcomings • Limited number of subjects • Varied rating tendency • Underlying interactions

36. User Satisfaction Relationship between input methods and user satisfaction Pinyin is preferred while stroke possess a high variation Relationship between key type and user satisfaction Button and touch-screen posses similar rating, and all vary significantly Full keyboard Relationship between key layout and user satisfaction Treatment B(Num) and C(Full), satisfy users better than others, while D(Full) does not differ from other Nums significantly

37. User Satisfaction Underlying interactions exist Input method and key layout share similar pattern in user satisfaction

38. User Satisfaction Negative correlation was found between key type and other two variables, speed and error rate

39. Q&A Thanks!