It's time to improve the touchscreen keyboard.

The majority of mini–QWERTY keyboard substitution errors are row errors accounting for 55.3% of the substitution errors and 22.2% of the total errors.

In comparison, there are relatively few transpositions (5.2%).

The Twidor software was configured to use the MacKenzie and Soukoreff phrase set [MacKenzie and Soukoreff 2003], a set of 500 phrases representative of the English language. The phrases range from 16 to 43 characters with an average length of 28 characters. The phrase set was modified to use only American English spellings and display only lower case letters and spaces (no punctuation or capitalization).

“T9 typing rates range from 9 wpm for novices to 20 wpm for experts [James and Reischel 2001].”

“Novice multi–tap users begin typing at approximately 8 wordsper minute (wpm) [Butts and Cockburn 2002; James and Reischel 2001] with experienced users reaching speeds in the 16–20 wpm range [MacKenzie et al. 2001; Lyons et al.2004].”

“Wireless email is a feature desired by 81% of consumers” (2006)

“Subjects average over 31 words per minute (wpm) at over 95% accuracy for the first session and increase to an average of 59 wpm at almost 93% accuracy by the twentieth.”

Don Norman