“Everything changes with touchscreens. On today’s smartphones, almost the entire front surface is a screen. Users need to be able to see the whole screen, and may also need to touch any part of it to provide input. Since my old data was mostly from observations of users in the lab-using keyboard-centric devices in too many cases – I needed to do some new research on current devices. My data needed to be more unimpeachable, both in terms of its scale and the testing environment of my research.”
How to elaborate on just one facet of mobile devices: portrait versus landscape.