By now it's almost a cliché for usability books to exhort readers to conduct their own testing. With all the information out thereincluding our own bookwhy are we so emphatic about testing? Isn't it enough for you to benefit from the results of our huge number of tests and simply apply the guidelines to your designs?
The reason is because usability guidelines are based on three levels of research:
This book encompasses the first type of guidelines. They are related to issues that we see again and again, among all kinds of users on all kinds of sites, so they are relevant to the vast majority of sites. The many reports available on our Web site cover many of the second type of guidelines. The third type of guidelines relates to circumstances that may be specific to your site, and only you can discover what these are.
It is important to stress that while the guidelines in this book are valid for the vast majority of cases, they are not for all cases. Human behavior is so variable that you may find they don't apply to your site perhaps ten percent of the time. For 1,000 guidelines, that could mean that 100 may not applysmall in the big scheme of things but a sizable number if it is your site. (In fact, we have documented many more than 1,000 usability guidelines, though we are covering only the most important ones in this book.) Thus it's simultaneously true that you should follow the vast majority of guidelines and you should not follow some guidelines.
Some issues are so specific to your site, they aren't covered in any report. That's why you always need to conduct testing with your own users.
What should you do about those specialized design questions that are beyond the scope of this book? And how do you know whether they are important enough to warrant deviating from a general guideline? For both questions, you can only discover the answers through your own user testing. Let's look at an example: a site that sells used watches, as shown in this screen shot.
Users can buy and sell used watches on this site. The long text in the middle of the page violates the general guidelines for writing on the Web. It is preferable for users to see their options in easily scannable menus.
The dense text was probably included for search engine optimizationan attempt to squeeze as many brand names as possible onto the homepage. It would have been better business to design focused topic pages for each brand and aim to have those pages rank highly for users who know what brand they want. If users land directly on a page showing multiple watches from their desired manufacturer, they are more likely to find something that appeals to them. In contrast, somebody who searches for, say, "IWC Mark 10" might find this homepage but would be likely to leave the site without buying because the watch is not visible, nor easy to find.
You might ask, "What's the harm in attracting users even if you don't have the product they want? The worst they can do is leave." But actually, they can do worse than leaving: They can never return. Once users have been disappointed several times after clicking your links in a search engine, they may well decide to ignore your site in the future. Ironically, this would include cases in which you actually do carry the product they want.
Watches.co.uk should conform to the general guidelines for all Web sites, such as minimizing dense text. The site does follow the general guideline to highlight what's inside it by showcasing examples on the homepage. The general guideline cannot state exactly how individual sites should reveal content, but this site's approach of showing photos and prices of some featured watches is good implementation of the guideline.
Since watches.co.uk belongs to the genre of e-commerce sites, its designer should also follow the hundreds of more specialized guidelines for e-commerce in our specialized report. For example, we have developed a host of detailed guidelines for site shopping carts, including one to show the cart at the top of all pages, as this site does. Unfortunately, however, the site violates another guidelineto call the cart a "cart"by calling the cart a "basket." This is an acceptable but slightly less optimal alternative because people scan for the word "cart" first.
Finally, since watches.co.uk sells used watchesas opposed to books, flowers, computers, airline tickets, or any of a thousand other itemsits designers should follow specific guidelines for selling watches and used items. Some guidelines for selling used items can be gleaned from usability studies of online used-goods vendors, from eBay to antiquarian booksellers. To determine guidelines specific to selling watches, however, the company must do custom research with the site's own users.
The guidelines in this book will help you develop your site, no matter what type of site you are working on. But you should also read additional reports on more specific issues. And some issues are so specific to your site, they aren't covered in any report. There's just no getting around it: To make your site a leader in its genre, you always need to conduct testing with your own users.
In sum, this book condenses thousands of usability findings into a fairly small number of key principles by emphasizing the ones that will have the most impact on your projects. We give you the facts about the top design flaws and strengths on Web sites today and compare them to those of previous years. By the time you have finished reading this book, you will know what works and doesn't work, and how to make your Web site more usable, and thus, more successful.