Tablet vs. mobile computing

One of the drawbacks to working in “mobile computing” is that “mobile” is an ambiguous term. Most times when someone refers to mobile computing these days, they are actually referring to smart phones. However, tablets are also mobile and exhibit different usage characteristics than smart phones, talking generically about mobile user experiences and mobile interaction when you really mean smart phone UX and interaction is problematic. And of course laptops are mobile too, with usage characteristics that differ from both smart phones and tablets.

And it gets even trickier. Not all tablets are alike. Having played with both 7″ and 10″ tablets, I actually think they exhibit their own individual usage characteristics. And for that matter, I think there are even subtle differences between 4:3 aspect ratio tablets and 16:9 tablets (the former are, I think, better for browsing websites and text, while the latter are better for watching 16:9 movies).

Rather than discussing the ambiguous “mobile computing”, then, I think we should really discuss tablet computing. Let’s be honest: smart phones these days are really just small tablets that happen to also make phone calls. They’re touch-sensitive computers first, phones second. If we just consider them to be tablets, we can move beyond the whole phone vs. tablet thing and instead consider the impact of size on tablets.

I think there are at least three classes of tablets, each with different usage characteristics:

• 3-4″ tablets, which are today’s smart phones (and iPod Touches). They’re small enough to carry around in pockets, so they’re the tablets people are most likely to have with them. However, their small form factor means that it’s tough to get “real work” done with them, so they tend to lend themselves to frequent, intermittent, and short interactions.
• 7″ tablets. The Nook and Samsung’s original Galaxy Tab fall into this class. They’re still pocketable, but the pocket is likely to be a suitcoat or jacket pocket (or back pocket, provided you’re careful before sitting down). The main advantage of this class is that they’re very easy to hold in a single hand, so they’re very comfortable to read from or to use when walking around. However, viewing larger amounts of information (such as the NY Times desktop web page) tends to feel somewhat like using a smartphone for the same task: you feel like you’re viewing the information through a small porthole, so you pan and zoom a lot. I have to confess I originally thought no one would want a 7″ tablet, but after playing with one for awhile now I think the ease of holding it in a single hand is not to be overlooked.
• 9-10″ tablets. Yes, the iPad 2 is lighter. But these larger tablets are still more about use while seated where you can bring both hands to bear. Viewing larger amounts of information is more comfortable (I can easily browse the NY Times web page on a 10″ tablet), and this is my preferred form factor for viewing videos/movies and browsing the web. But for sustained reading (such as an ebook), I personally find this larger form factor a little too cumbersome.

Those categories may not be exclusive; we may find other form factors that are useful for slightly different cases (or even better suited for these existing cases). But so far, my basic rule of thumb is that 3-4″ is for ubiquitous access to information, 7″ is great for reading, and 10″ is great for browsing the web and watching movies. Mapping those patterns to business use cases is left as an exercise to the reader (and this researcher, of course).

Regardless of what categories of tablets we finally end up with, I’d like to encourage everyone to move away from “mobile computing” and toward “tablet computing”, at least when focusing on the use of particular types of devices (i.e., smart phones). Mobile computing should be about computing while mobile regardless of device type (and should include laptop use). Tablet computing should focus on interaction with touch-sensitive tablets, and should explicitly include an exploration of the impact of different tablet sizes and form factors.