An Evaluation of Text-Entry in Palm OS – Graffiti and the Virtual Keyboard

Abstract

The handheld organizer or personal digital assistant (PDA) is rapidly becoming a popular organizational tool, and there is a need for evaluation of alphanumeric character entry on these devices. The Palm operating system, the most common PDA operating system on the market, uses two methods for character entry, an on-screen virtual keyboard and a single-character handwriting recognition system called Graffiti. An initial experiment was conducted to investigate the character entry rates of novice and expert users of the device for the two methods of input. Experts were found to reach an average rate of 21 words per minute (wpm) using Graffiti and 18 wpm using the virtual keyboard. Novices were able to use Graffiti at a rate of 7 wpm and the virtual keyboard at 16 wpm. These character entry rates are evaluated with respect to some theoretical limitations, a predicted rate of entry based on Fitts' and the Hick-Hyman laws for the virtual keyboard, and pen and paper printing for Graffiti. The potential gain for new character entry systems and opportunities for improvement are discussed.

Get full access to this article

View all access options for this article.

References

Card

S. K.

Moran

T. P.

Newell

(1983). The Psychology of Human-Computer Interaction. (Lawrence Erlbaum, Hillsdale, NJ).

Consumer Reports. (May 2001). Data to go. Consumer Reports, 66(5), 20–23.

Goldberg

Richardson

(1993). Touch-typing with a stylus. Proceedings of the INTERCHI '93 Conference on Human Factors in Computer Systems, 80–87.

MacKenzie

I. S.

Nonnecke

R. B.

McQueen

J. C.

Riddersma

Metz

(1994). A comparison of three methods of character entry on pen-based computers. Proceedings of the Human Factors and Ergonomics Society 38th Annual Meeting, 330–334.

Mackenzie

I. S.

Zhang

S. X.

, (1997). The immediate usability of Graffiti. Proceedings of Graphics Interface 97, 129–137.

Mackenzie

I. S.

Zhang

S. X.

, (1999). The design and evaluation of a high-performance soft keyboard. Proceedings of the SIG-CHI Conference on Human factors in computing systems, 25–31.

Mackenzie

I. S.

Zhang

S. X.

Soukoreff

R. W.

, (1999). Text entry using soft keyboards. Behaviour & Information Technology, 18(4), 235–244.

Palm

Computing.

(1995, January). Suddenly Newton understands everything you write. Pen Computing Magazine, p. 9.

Soukoreff

R. W.

Mackenzie

I. S.

(1995). Theoretical upper and lower bounds on typing speed using a stylus and a soft keyboard. Behaviour & Information Technology, 14(6), 370–379.

10.

Soukoreff

R. W.

MacKenzie

I. S.

(2001). Measuring errors in text entry tasks: An application of the Levenshtein String Distance Statistic. Extended Abstracts of the SIG-CHI Conference on Human factors in computing systems, 319–320.

11.

Zhai

Barton

S. A.

(2001). Alphabetically biased virtual keyboards are easier to use layout does matter. Extended Abstracts of the SIG-CHI Conference on Human factors in computing systems, 321–32.