6. Asking for the Same Info Twice
Users shouldn’t have to enter the same information more than once. After all, computers are pretty good at remembering data. The only reason users have to repeat themselves is because programmers get lazy and don’t transfer the answers from one part of the app to another.

7. No Default Values
Defaults help users in many ways. Most importantly, defaults can: speed up the interaction by freeing users from having to specify a value if the default is acceptable; teach, by example, the type of answer that is appropriate for the question; and direct novice users toward a safe or common outcome, by letting them accept the default if they don’t know what else to do.

Because I used Liste Rouge Paris as a bad example under Mistake #1a, I thought I’d play nice and use them as a good example here. The tailor offers 15 different collar styles (among many other options) for people ordering custom-designed shirts. Luckily, they also provide good defaults for each of the many choices. In testing, this proved helpful to our first-time user, because the defaults steered him toward the most common or appropriate options when he didn’t have a particular preference.

Dialog to specify your shirt’s collar on www.listerouge-paris.com (3 of 15 styles shown).

8. Dumping Users into the App
Most Web-based applications are ephemeral applications that users encounter as a by-product of their surfing. Even if users deliberately seek out a new app, they often approach it without a conceptual model of how it works. People don’t know the workflow or the steps, they don’t know the expected outcome, and they don’t know the basic concepts that they’ll be manipulating. For traditional applications, this is less of a problem. Even if someone has never used PowerPoint, they’ve probably seen a slide presentation. Thus, a new PowerPoint user will typically have at least a bare-bones understanding of the application before double-clicking the icon for the first time.

For mission-critical applications, you can often assume that most users have tried the app many times before. You can also often assume that new users will get some training before seeing the UI on their own. At the minimum, they’ll usually have nearby colleagues who can give them a few pointers on the basics. And a good boss will give new hires some background info as to why they’re being asked to use the application and what they’re supposed to accomplish with it. Sadly, none of these aides to understanding apply for most Web-based applications. They don’t even apply for many ephemeral intranet applications.

Usability suffers when users are dumped directly into an application’s guts without any set-up to give them an idea of what’s going to happen. Unfortunately, most users won’t read a lot of upfront instructions, so you might have to offer them in a short bulleted list or through a single image that lets them grok the application’s main point in one view.

As an example, our test user who was trying to order a custom-tailored shirt was highly confused when the first screen in Hamilton Shirts’ “Create Your Shirt” process displayed a fully designed shirt with an “Add to Bag” button. This screen mixed two metaphors: a configurator and an e-commerce product screen.

This is a case where a default value isn’t helpful: people who want to design their own shirt are unlikely to want to buy a pre-designed shirt on the first screen.

(This screen also suffers from Mistake #1: non-standard GUI controls. In addition to its non-standard drop-down selection menus in a tabbed dialog that doesn’t look enough like tabs, the screen has a non-standard way of paging through additional fabric swatches. Users are less likely to understand how to select fabrics when the controls are presented in this manner.) Our test user never understood the process of designing his own shirt on this site and ultimately took his business elsewhere.

9. Not Indicating How Info Will Be Used
The worst instance of forcing users through a workflow without making the outcome clear is worth singling out as a separate mistake: Asking users to enter information without telling them what you’ll use it for.

A classic example is the “nickname” field in the registration process for a bulletin board application. Many users don’t realize the nickname will be used to identify them in their postings for the rest of eternity — so they often enter something inappropriate.

As another example, we once tested an e-commerce site that smacked users with a demand for their ZIP code before they could view product pages. This was a big turn-off and many users left the site due to privacy concerns. People hate snoopy sites. An alternative design worked much better: It explained that the site needed to know the user’s location so it could state shipping charges for the very heavy products in question.

10. System-Centric Features
Too many applications expose their dirty laundry, offering features that reflect the system’s internal view of the data rather than users’ understanding of the problem space.

In our current study, one user wanted to reallocate her retirement savings among various investments offered by her company’s plan (for example, to invest more in bonds and less in stocks). She thought she did this correctly, but in fact she had changed only the allocation of future additions to her retirement account. Her existing investments remained unchanged. As far as the mutual funds company is concerned, new investments and current investments are treated differently. Reallocating future additions means changing the funds they’ll buy when the employer transfers money into the account. Reallocating current investments means selling some of the holdings in existing mutual funds and using the proceeds to buy into other funds.

The key insights here? Our test user didn’t have this distinction between new and old money; she simply wanted her retirement savings allocated according to her revised investment strategy.

Even users who understand the distinction between new and old money might prefer to treat their retirement savings as a single unit rather than make separate decisions (and issue separate commands) for the new and old money. It would probably be better to offer a prominent feature for changing the entire account’s allocation, and use progressive disclosure to reveal expert settings for users who want to make the more detailed distinction between the two classes of money.

Bonus Mistake: Reset Button on Web Forms
This mistake relates to Web forms, but because so many applications are rich in forms, I’ll mention it here: It’s almost always wrong to have a Reset button on a Web form.

The reset button clears the user’s entire input and returns the form to its pristine state. Users would want that only if they’re repeatedly completing the same form with completely different data, which almost never happens on websites. (Call center operators are a different matter.) Making it easy for users to destroy their work in a single click violates one of the most basic usability principles, which is to respect and protect the user’s work at almost any cost. (That’s why you need confirmation dialogs for the most destructive actions.)