Good UI design is KEY
Last time, I discussed why design considerations are fairly important. Now, I want to discuss some of the actual principles in design. Today, I want to discuss some Human-Computer Interaction principles in general, as they are of more general use to everybody. I also want to note the principles involved specifically with mobile apps and mobile health apps, but to remain brief, I will stick to one topic at a time. Honestly, I could probably write pages on this subject: It is important, I began a class on it some time ago, and there is enough material to teach entire courses on the topic (see: 1 and 2 , at Rice.)
Most general design principle information actually comes from psychological principles dealing with perception, attention, and memory. We use these higher level functions to interact in the world and with our devices, so they must take them into account. In An Introduction to Human Factors Engineering, as pulled from Wikipedia, Christopher Wickens et al. defined 13 principles of display design, which can be readily used in mobile app design as well as in designing other things, as they mostly deal with the higher level cognitive abilities I just mentioned. They can divided into a few subgroups, of which I shall talk about instead of the actual principles, because that would take too long. If you’re interested though, take a look at the above link.
Perceptual Principles
These principles revolve around the idea that, as people, we can only perceive reality in certain ways, and design needs to accommodate for that. The size of the display we have is limited (iPhone or Android or other smartphone screens), and they must be readable to the majority of the patients, many of whom are old and are losing eyesight. Alternatively, we can remove as much text as possible and use symbolic stand-ins and videos. One of the principles, redundancy gain, is rather useful, as it suggests that by presenting a signal more than once, even in different physical forms, the client will understand it better.
Mental Model Principles
We have past experience with the way the world is organized, so going into an app or other resource, we have some idea about how they are supposed to work. This is one of the large reasons why testing a project with a designed interface with a small sample size is good: the developers are likely to be tech-savvy, and if their population does not have the same expertise, ideas that seem simple to the devs will be difficult for the users.
I’m using twice, but its so relevant!
Principles Based on Attention
A display will have the client divide their attention into multiple areas. The distance between areas should be minimized to reduce the small but certainly present cognitive load that results from the distance between elements in a display. Using multiple resources to present information helps here too.
Memory Principles
Generally, we want to reduce the amount of memory clients have to spend trying to make an application function. We can do that by “piggybacking” on their existing knowledge (as I mentioned earlier), by predicting actions for them (e.g. pulling up a list of what exercises they will need to do that day), and by being consistent across displays.
The Face-up side is not immediately obvious. Not good design, at least to us
The design strategies themselves, of course go much deeper than that, but as Wickens et al. proved, one could write an entire book on the matter. These considerations, however, will certainly be useful in app design.