The Effects of Keyboard Layout and Size on Smartphone Typing Performance

Abstract

Usability and typing performance on a smartphone with two unique QWERTY keyboard layouts (standard vs. curved) on two phone sizes (4.0-inch vs. 5.5-inch displays) was investigated in this study. The effect of hand posture was also investigated (one- vs. two-thumbs). Results show users typed the slowest when using one thumb with the curved keyboard on the small phone (15 WPM), and the fastest when using two thumbs with the standard keyboard on the large phone (24 WPM). Typing performance with the curved keyboard on the large phone size (19 WPM) did not differ between typing with one thumb using the standard keyboard on the large or small phone, or with two thumbs using the standard keyboard on the small phone. Error rates were higher when using the curved keyboard, regardless of phone size. Subjectively, the curved keyboard was rated inferior for both phone sizes in comparison to the standard layout.