<TFM> Number 1.10

About TFM | Archives | Number 1.10 (originally published October 2001)

Conducting a web site evaluation

Heuristic evaluation is one way to quickly and inexpensively evaluate a user interface. The process requires that a small set of testers (or “evaluators”) examine the interface and judge its compliance with recognized usability principles (the “heuristics”). The purpose is to identify any usability issues so that they can be addressed as part of an iterative design process.

Originally designed for software evaulation, the principles work well for web sites.

The following evaluation criteria are based on Jakob Nielsen’s work (numbers 1-10), other readings, and personal experience. For each cateogry, the web site is graded as follows:

0 = Site category is optimized for usability
1 = Site category has only minor usability issues
2 = Site needs only minor changes optimize usability
3 = Site has fair usablity, medium-class problems
4 = Major issues in this category, priority for repair
5 = Catastrophic issues in this category; site not usable in this category;
repair here is mandatory

1. Visibility of System Status

In addition to providing feedback after executing an action, web sites must answer these two questions: “Where am I?” and “Where can I go from here?” This is particularly important because many visitors don’t enter the web site through the front door (home page) — they enter “inside” the site via a link from a search engine or a link from a friend. Not only should the navigation answer these questions, the page should have a meaningful title (in the title tag, for bookmarks) and URLs should be human-readable and forwardable.

Good example of feedback: the Orbitz.com intermediary screen which appears while searching database for airline flights.

2. Match Between the System and the Real World

The system should speak the users’ language, using words, phrases and concepts that are familiar to the user, rather than system-oriented terms. This requires, of course, that you have a good understanding of the potential visitors to your web site.

3. User Control and Freedom

The web is predicated on user-control — thus true linear web site design is an anethema to the savvy-web user (under most circumstances). In addition, site visitors often choose application functions (or web pages) by mistake, so they need a clearly marked “emergency exit” to leave without having to go through an extended dialogue with the browser’s back button. Examples include clearly marked “home” or “sitemap” links.

4. Consistency and Standards

Not only should words be consistent across the site — but navigation elements should be consistent in look-and-feel as well as placement. Establish web site standards and encourage conformance in cases of distributed authorship.

5. Error Prevention

The best design is one that prevents a problem from occurring. The best way to avoid errors is to test, test, and test! However, when errors do occur (and they will), provide user-friendly messages, not than geek-speak.

6. Recognition Rather than Recall

Make sure objects, actions, and options are highly visible. Your site visitors shouldn’t have to remember information between different parts of the site in order to function in other parts.

7. Flexibility and Ease of Use

Accelerators, which may be unseen by the novice user, can speed up the interaction for the expert user and allow the system to cater to both experts and novices. Consider Amazon.com. They allow visitors to save personal information so that each time the customer makes another purchase, she can retrieve her information with a single click.

8. Aesthetic and Minimalist Design

Extraneous information on a page is a distraction and requires an HTTP call to the server – slowing down the process of loading a page.

8a. Design/Navigation

Does the site navigation conform to web norms (location, functionality, colors)? Are navigation elements consistent in placement? Is navigation order logical (ordered by alpha, chronologically, or some “orderly” method)? Does the site rely on navigation (good) or search (not as good) to find information? Are hyperlinks clearly differentiated? Are underlines used for anything other than hyperlinks?

8b. Design/Accessiblity

Consider universal design/accessible design. Use ALT tags, provide information in alternative formats, don’t require Java or Flash in order to navigate an entire site.

8c. Design/Other

Splash pages:
The web is not a book … or a software application. Avoid splash pages. Avoid “skip this intro” Flash introductions.

Animation:
Movement is not only distracting, it is physiologically hard on the eye if the visitor is trying to avoid it.

Banner Ads:
If it looks like an ad — or is placed where the visitor has come to expect an ad — don’t expect visitors to read/see it. Research shows how well visitors “avoid” banner ads.

9. Help Users Recognise, Diagnose, and Recover from Errors

Errors will occur despite all our efforts to prevent them. Error messages should be expressed in plain language. They should detail the problem, and constructively suggest a solution.

For example, if a form is completed incorrectly, the error message should not only alert the visitor but also identify which fields are problematic. The best time to alert visitors about incomplete forms is prior to submission!

10. Help and Documentation

Ideally, every online system could be used without documentation. If your web site requires a detailed “help” section to operate, consider this a serious design flaw. Contact link easy-to-find.

11. Content

Readabilty:
Does the site use fonts optimized for the screen? Are font sizes readable or easily adjustable? Does the site specify font faces that are inclusive for all systems? Are colors used indiscriminately? Is content designed for easy scanning?

Privacy Policy: Present and easy to find (and understand) if any personal data is required or if the site uses cookies.

12. My catch-all list

Site provides quick assistance if I forget login or password.
Provides a contact for the web site that is easy to find — and provides a
copy of any ‘form-mail’.
Each page has a meaningful title and can be bookmarked.
URLs are human-readable and forwardable.
Shopping baskets make it easy to change quantities.
Form content doesn’t vanish on “back” if a field is missing.
Forms show what data are required — and only reasonable data are required.
Does site require Java or Flash (or other ‘extra tech’)
without warning or without due cause?
Load time : reasonable?
Does the site demand that I use a specific browser?
Does music auto-load? Is there an off-switch?
Tone? Is it conversational or formal? Is it painfully hip?
In a nutshell, is it appropriate to the site and the audience?