Note: This post was originally quoted on Wired.com Gadget Lab post, How the Kindle Fire Could Make 7-Inch Tablets Huge.

Wired Magazine recently posed some interesting questions:

• How would an experience on a 7-inch tablet (like Amazonâ€s Kindle Fire) differ from one on a 9.7-inch tablet like the iPad?

• How does the size of the tablet device play into the application design, and how the user interacts with the device?

• Do smaller 7-inch tablets have the potential to be as popular as the larger iPad, from a user experience perspective?

Here are my thoughts on the subject:

I think mini-tablets (7 inch or smaller) have the potential to be as popular as iPad-sized tablets, but the types of applications and the context and length of use between might be very different. As I wrote in my book, Designing Search: UX Strategies for eCommerce Success (Wiley, 2011) in doing tablet user research we find that most people purchase iPad sized tablets for use at home as a shared media-consumption device, the way an Alpha-TV was used in the 1950s. iPad-sized tablets are heavy, expensive and fragile enough for most people to think twice about traveling with them, and most larger tablets are being purchased without 3-G wireless connection plans.

Because the difficulty of text input and direct content manipulation make most office work activities a challenge, tablets in general tend to be somewhat biased toward specific “light†activities: reading news, playing video, and of course gaming. Tablets are also moving into the territory of email, social media, and light work tasks, but this dynamic is changing slowly, partly because iOS and Android are both “personal†operating systems, so they do not gracefully handle login by multiple members of the family, the way full-featured Mac OS and Windows do. Most people would not want their 6-year old tyke who loves to play Angry Birds, to also have direct access to their work email, or Amazon One-Click Checkout feature. Until OS and Android change to allow multiple login (or market penetration increases sufficiently to allow multiple large tablets within the same household) the larger, iPad-sized tablets are going to continue to be biased toward anonymous family-based media consumption. One of the “quick wins†I recommend in my book is having individual apps handle multiple logins or profiles – until the login is fixed, this is a must interim “design hack†for the privacy problem.

Although the jury is still out, this privacy dynamic could be very different for mini-tablets. Lower price-point could engender the public to purchase truly personal mini-tablets, thus removing the privacy issue. Mini tablets (especially in an attractive, durable, drop-resistant cases) can also be stowed away in purses and backpacks more easily and taken along on more outings than their heavier, more expensive and fragile iPad-sized counterparts. Essentially, smaller tablets can be thought of as individual mobile devices, with use patterns similar to those of mobile phones. Of course, on the flip side, few consumers can currently justify purchasing a second mobile phone, and that appears to be the Achilles†Heel of the mini-tablets – the publicâ€s perception that they are too close to smartphones (yet not as capable without the 3G wireless plans) to justify purchasing the second device.

From the standpoint of the interface design, itâ€s a mistake to think of larger iPad-sized tablets and their mini-counterparts the same way. The ergonomics of each device are fairly different. Most mini-tablets (as are most smartphones) can usually be held in one hand, while multi-tasking or literally on the move, while holding on to the overhead bar in the Metro car. One-handed mini-tablet operation is possible because the device is lightweight and a typical adult can reach most of the controls on the screen with their right thumb, while holding the device in the same hand. It makes sense then for designers to optimize the touch controls accordingly for a one-handed operation. Even in most games, milti-touch interface controls on the mini-tablet are also somewhat limited to a smaller sub-set of touch gestures (such as a simple swipe) that can be comfortably executed on a small screen. Instead, accelerometer-driven controls such as shaking, tilting and rotating the entire device are called upon to shoulder some of the interaction complexity.

The situation could not be more different for larger, iPad-sized tablets. Larger, heavier devices dictate that they be at a minimum, held in two hands or rested on some surface or the lap of their owner. In addition, the extra two inches of the screen make it impossible to reach all of the controls with one hand while also holding the device with the same hand. Thus it makes sense to place touch controls for larger tablets vertically, along each side of the device, while generally avoiding the bottom of the screen (because the bottom of the screen is awkward to reach while the tablet is partially resting on the lap or some other surface – the preferred position for most uses). Accelerometer controls such as shaking are usually impractical, and even tilting and rotating is done infrequently. On the flip-side, a larger surface and two free hands allow for a dizzying variety of possible multi-touch gestures, creating a rich, intuitive touch-screen interface. There are even rumors that the multi-finger tap, an excellent idea presented by Josh Clark, will be used in place of a home button on future versions of the iPad. (You can read much more about the iPad and mobile design quick wins in my book Designing Search: UX Strategies for eCommerce Success (Wiley, 2011) Free Chapter 1 is now available for download.)

In closing, the purchasing decision for larger vs. mini-tablet seems to be centered on how the device will be used. It is all about the niche benefit – if the customers can justify purchasing cheaper books or are attracted to being able to carry their entire library everywhere with them, they might very well be tempted to purchase a Kindle Fire before they buy an iPad. As anecdotal evidence, at least in the San Francisco Bay Area, it is now a fairly common sight on public transportation to see people who carry their mobile phone, laptop and a Kindle. One trend seems to be clear: market studies show that the iPad tablet sales do not cannibalize sales of any other device, except for e-readers. Thus it is safe to say that despite their ergonomic differences, mini-tablets and larger tablets are currently engaged in the head-to-head market competition.

Interested in learning practical mobile and tablet design skills? Check out my workshop.

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Image credit:

matt buchanan [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)] https://commons.wikimedia.org/wiki/File:Steve_Jobs_with_the_Apple_iPad_no_logo_(cropped).jpg