The impact of letters’ relative position on mobile text input performance

Keypad text input based on thumbs is still the main mobile text input method. So its efficiency is most important to the mobile usability. In the current, most researches on mobile keypad´s ergonomics focus on text input methods, while some scholars improve the efficiency of text input by optimizing the keypad symbols layout However such studies are all about English text input and there are only a few studies on the Chinese text input to the present. Aimed at the deficiency of such studies, the author in the paper made an experiment based on Pinyin text method to discuss if there was difference between performances of two Pinyin letters input in succession under the different relative positions of the buttons. The results showed that the letters´ relative position was one of the factors that influenced the mobile text input performance.