INTERESTING! In general, how devices are used in the real world, maybe even touch on resilience, on glanceability.

People use their phone in real environments, so we must set aside the assumption that the interaction is entirely with a flat glass screen. The way people hold and tap changes by their grip, and that changes because they are carrying items, talking to others or opening doors.

All people are, as Robin Christopherson says, temporarily disabled, and designing like this can assure your mobile device works for every user all the time. We work in loud environments, with glare and rain, cannot touch the device, are distracted. Subtle cues may not work, so multi-encode indicators and responses to interaction.

Environment matters

...talk about the study on how accuracy changes when carrying things. Specifics, with images of inaccuracy, etc...

Sound and

Resilience

... which segues into this.

Glancability

... some basic guidelines on notifications, but make sure we do not stray too far afield. This is about touch, but make sure it's about sense at least...

...So, wait for users, don’t pop up messages for short periods, don’t beep if they are likely to be in loud environments. Maybe even Christopherson’s Temporary Disability, and touch on how you must design also for low-vision but designing for real environments gets you a long way there…

Don’t forget cases and bezels

Despite the increasing prevalence of edge gestures, dragging items on or off the screen, we have to remember that touchscreen devices aren’t really flat on top.

Plenty have a raised bezel to protect the screen, and many, many users put cases on. What this means is that many users cannot actually get to the edge of the screen. If they really press their finger they can get skin onto the edge, but remember the screen senses the center of your contact area so even if you can push your finger hard enough to get to the edge of the screen, the sensed point may be well inside the edge.

If you want to place items right against the edges, or have edge gestures, go ahead. But don’t only allow them to work at 1 pixel from the edge, or originating off screen. Provide some padding.

The safe zone here is somewhere between half and the full width of the accuracy by zone. Along the sides, I use 6-8 mm, but for the top and bottom I would extend this to about 10-12 mm.

...Segue to the next section on designing at scale. Design /for/ people then design /like/ the way people work.

References