Click here to buy from Amazon.Principles exist at a higher level than any pattern. They can be considered patterns for the patterns, if you will. Each pattern, and each detail of interactive or presentational design, should adhere to each of these principles at all times.

Each section and chapter in the book will begin with a discussion of the core principles for their sections, as well as other helpful guidelines that apply to those patterns.

Each of these principles could be discussed in great detail, and in fact we could have organized the book differently so that each of them was a chapter, with patterns associated to it. In the interest of clarity, the discussion of each of these is limited. If you are interested in further details on the rationale, these are generally discussed in greater detail within the patterns they apply to, as well as the chapter introductions.

Respect User-Entered data

Input is hard. Users slip. You have a new phone, or are borrowing someone else’s, and someone jogs your arm: suddenly minutes of typing is gone. Do whatever it takes to preserve user data—from saving as the user types so that auto-complete can bring lost input back, to not clearing forms on error, to planning for a loss of connection. Consider con- texts and plan for crises and real-world behaviors, not bench tops and labs.

Realize That Mobiles Are Personal

Although security is important, there is no longer the need to assume that maybe the website is being viewed on a library computer. Mobiles can be presumed to be “one device for one person,” and no one wants to have to regularly tell his device his name, location, or favorite music. Only implement passwords and clear personal information when required by law or regulation, and take other types of reasonable and transparent precautions to prevent misuse of information.

Ensure That Lives Take Precedence

Mobiles are contextual, meaning they are used alongside people’s actual lives. Desktops (and some other devices) can suck people in, so you can go ahead and issue alerts that blink in the corner of the screen and they will be noticed. Mobiles are glanced at, used in gaps between conversation and driving and watching TV. They are even used to enhance these other experiences. So make sure they don’t interrupt unless they have to. And if they have to, make sure they interrupt in a way in which the interruption will be noticed. A blinking LED, for example, is easily missed when a device is glanced at for a fraction of a second.

Realize That Mobiles Must Work in All Contexts

Make the device behave appropriately, or allow users to make the device behave appro- priately, to make it work where they are. Most devices are too bright at night, making it hard to read that last email before bedtime, or to tell what time it is when the alarm goes off first thing in the morning. If the phone doesn’t have a good way to change brightness, your app can override it or your website can just have a dark/light switch. Think about the context in which the device will be used.

Use Your Sensors and Use Your Smarts

Whenever possible, perform actions for the user based on sensors and user data. Why should you have to silence your phone for a meeting, when the phone knows where you physically are and knows from your calendar that you have a meeting in that room right now? Mobiles can be better than computers, because of their personal nature and their sensors. Use them.

Realize That User Tasks Usually Take Precedence

If the user initiates a task, and especially if the user is in the middle of a task, do not inter- rupt the user so that the task is ruined. When the user is typing an SMS, feel free to beep, but do not change the focus so that the user is suddenly typing in another field. And never cancel the operation to take the user to another page, losing her information.

Ensure Consistency

Whatever the rest of the application does, do that. And the application standards should follow the edict: "whatever the OS does, do that." Even if the OS does something dumb, it’s probably what the user expects, so changing the paradigm generally results in more problems than solutions.

Respect Information

Although presentation and visualization can be used to clarify information, or view it in different ways, do not modify the fundamental truth for saving space, or because you do not understand the value of it. More information than you might expect rises to life/ health/safety levels with the ubiquity of mobiles. Weather, for example, must be presented perfectly accurately. Know the difference between precision and accuracy, and under- stand implications of meter types, relative values, off-scale errors, and more. Naturally, these will change over time. Just in the past five years we have changed or expanded these several times. Be aware of the reasons these principles exist, and keep abreast of the industry so that you are aware of changes.

Although we feel these principles are universal today, you are very free to disagree. Many others do, and they have their own principles, or variations on the understanding of what these mean. Just be sure you develop a set of design principles or objectives for your work or your project, and then stick to them.


Next: Part I Page


Discuss & Add

Please do not change content above this line, as it's a perfect match with the printed book. Everything else you want to add goes down here.

How Mobile is Different from Desktop

In retrospect, maybe the first few sentences of the book were not the right way to go. I assumed anyone bothering to pick it up already knew why they needed it and had a handle on the basic info. But I regularly get questions that indicate there are misunderstandings.

Mobile is Different

Don't focus on screen size.

In many ways, mobile is not limited, but more capable than desktops.

Mobile is Huge

Other or different principles

I am constantly repurposing or changing these for specific clients. Occasionally I'll add one. I am going to start adding those as they might become real, universal principles in the future.

Users are the same person, everywhere

Single signon, single view, single data source. Regardless of touchpoint.

Make a new section

Just like this. If, for example, you want to argue about the differences between, say, Tidwell's Vertical Stack, and our general concept of the List, then add a section to discuss. If we're successful, we'll get to make a new edition and will take all these discussions into account.