Quasi-Qwerty soft keyboard optimization

It has been well understood that optimized soft keyboard layouts improve motor movement efficiency over the standard Qwerty layouts, but have the drawback of long initial visual search time for novice users. To ease the initial searching time on optimized soft keyboards, we explored "Quasi-Qwerty optimization" so that the resulting layouts are close to Qwerty. Our results show that a middle ground between the optimized but new, and the familiar (Qwerty) but inefficient does exist. We show that by allowing letters to move at most one step (key) away from their original positions on Qwerty in an optimization process, one can achieve about half of what free optimization could gain in movement efficiency. An experiment shows that due to users' familiarity with Qwerty, a layout with quasi Qwerty optimization could significantly reduce novice user's visual search time to a level between those of Qwerty and a freely optimized layout. The results in this work provide designers with a new quantitative understanding of the soft keyboard design space.