Usability Heuristic Evaluation

A 'heuristic' is a general guideline or conclusion that aids in an investigaton or analysis of something. A heuristic evaluation in usability, therefore, is when a group of usability experts evaluate your site's usability against a list of accepted guidelines and commonly accepted principles.

If you don't have the resources to hire usability experts, you could conduct the heuristic evaluation on your own site. It's not an ideal solution but any evaluation is far better than none at all.

Here are fifteen Web site usability heuristics.

Aesthetic and Minimalist Design

This heuristic states that your Web site should:

  • not offer more than is required for the user to perform a task: The more you have going on, on a Web page, the more effort the user has to put in to filter out the noise. Likewise, unneeded 'advanced' features can also make your page too confusing for new users. If you have to provide advanced features, put them on a separate page; and
  • be aesthetically pleasing: Removing unneeded elements from your site does not mean you have to get rid of design features or visual cues that make your site attractive. Great design is a perfect combination of minimalist and aesthetically pleasing design.

Consistency and Standards

Be consistent and follow accepted industry standards in your site design. There are many accepted conventions on the Internet.

Here are a couple of them:

  • The local navigation bar is usually displayed on the left of a page. Users may find it inconvenient and annoying, if the bar is moved to the right side; and
  • Most users know that blue underlined text represents a hyperlink. Changing the color, or removing the underline would likely confuse users.

Error Prevention and Recovery

Help users recover from an error by giving a precise description of what the error is, why it occured, and possible solutions for recovering from the error. Better still, prevent the error from occuring in the first place.

For example, make sure the links on your site aren't broken. In the event that your users find a missing page, provide a user-friendly "404 - File not found" error page, with help on how to find the missing page.

"404 - File not found" Redirection Advertising Services

Under no circumstances should you use a "404 - File not found" redirection advertising service in your site.

Your users are already frustrated when they don't find the page they are looking for. By redirecting them to another site, your users would be totally baffled. This is a good way of losing the visitor forever! It just isn't worth the extra cent or two that you make on the referral.

This clever advertising concept only benefits the service provider in the long run, not you, the site owner!

Flexibility and Efficiency of Use

This heuristic states that your Web site's interface should be flexible and efficient to use.

Flexibility

You should offer your users a number of options when it comes to finding content on your site.

These include:

  • Hyperlinks;
  • Basic search form;
  • Advanced search form;
  • Site map; and
  • Alphabetical index.

Efficiency

Your users should be able to achieve their goals in an efficient manner.

To maximize efficiency, you should:

  • word hyperlinks properly; preferably with the title of the page the link leads to;
  • make sure search results should include a description of the link, in addition to the title of the page;
  • design your site map in a logical manner; and
  • provide an alphabetical index which includes as many categories, content areas, departments and keywords as possible.

Help and Documentation

All Web sites require some form of help and documentation.

Help and documentation should:

  • be easy to find;
  • be focused on the user's tasks;
  • list possible solutions to assist the user in their most common tasks;
  • be organized in a manner that makes sense to the user; and
  • focus on helping the user achieve their goals.

Inverted-Pyramid Style of Writing

Traditionally, when you write, you start with a 'foundation' and gradually build to a conclusion in a pyramid style. You might write an essay or article using the following structure:

  1. Problem statement;
  2. Related work;
  3. Methodology;
  4. Results; and
  5. Conclusions.

Journalists, on the other-hand, use an inverted pyramid style. They generally start with the main conclusion and get progressively more detailed, like so:

  1. Conclusion;
  2. Supporting information; and
  3. Background and technical details.

Since Web users typically scan text, it is important to position main points at the beginning of the article, then go into more detail as needed.

Match the Web Site to the Real World

This heuristic states that the elements and terms used within your Web site should match those used in the real world as closely as possible.

Here are two examples:

  • Your Web site should use the user's natural language, not jargon or technical terms, unless they're Computer Science graduates - try to use "Cost Per Click" instead of "CPC", for example; and
  • In the real world, books have an "Index" to help readers find what they are looking for. You should also include one in your Web site to help your users find what they are looking for.

Minimize Download and Response Times

Web users often say speed, or rather the lack of it, is the biggest problem they face in using the Web.

Download times should be as low as possible.

Studies show that most Web users will tolerate a maximum page download time of eight seconds, before giving up, unless they are certain the page will contain the information they need.

The time is takes your Web site to respond is also important. Your site's search engine shouldn't take ten seconds to respond. Unlike with an application, it is harder to give a visual or audial cue to a Web user to reassure them that something is going on, so keep it quick!

If your site is inaccessible, because the server is down, users are also likely to give up on your Web site, so monitoring your server's uptime is also essential.

Protect Users' Work

Make sure that users never lose their work as a result of error, be it on their part, or the fault of the system.

For example, let's say a user fills up a shopping cart with products. Then, accidentally, their browser is closed, or it crashes. When they return to your site, the shopping cart should still contain the items they had previously added.

Nearly all users would be most frustrated to find an empty shopping cart. Many users probably couldn't be bothered to find and add the items to the user's shopping cart again, resulting in a lost sale for you.

Readability

Text should have high contrast to be easily readable. This means that the color or brightness of the text should be as different as possible to the background it is placed upon. Black text on a white background is the best option.

Be sensitive to the commonly accepted rules of the Web. If you're offering professional services you shouldn't really use a light colored text on a dark background. For example, white on black. This is really only suitable for entertainment Web sites that want look trendy or cool.

Don't forget to pay particular attention to the needs of the millions of users who suffer from color, or low-vision deficiencies. There are many people who cannot differentiate between green and red when they're right next to each other.

Real World Conventions

Use real world conventions by making information appear in a natural and logical order.

For example, traffic lights always have green (go) below red (stop). Don't reverse the order, or use different colors to signify "go" and "stop" in your Web site's interface. Ideally, you should also provide a textual cue, for those who are color-blind.

Recognition Rather Than Recall

Make objects, actions, and options easily recognizable and understandable.

For example, if you use icons in your site's navigation, use icons that are easily recognizable. If the user has to work out from memory what an icon is about, the icon needs to be improved. Don't make the user think too much!

Scannable Text

It is widely accepted that Web users scan Web pages rather than reading them in full.

We want to find the answer to what we are searching for, with minimum wasted effort and time. Life is short and time is expensive!

So, make your text scannable. Use bold headings, sub-headings and short paragraphs.

Try to get your message across with as few words as possible, without losing the value of what you're trying to say. As a general rule, in most documents you should be able to remove 25-50% of the words, without losing anything of real value!

User Control and Freedom

This heuristic states that you protect users from mistakes and give them the freedom and power to undo a mistake when they make one.

For example:

  • Don't make important irreversible actions easy to perform;
  • Offer undo and redo options;
  • Provide clearly marked "emergency exit" signs; and
  • Ask for 'confirmation' whenever you can, without being annoying or overprotective.

Visibility of Web site Status

This principle states that your Web site should always keep users informed about what is going on at any given moment.

For example, let's say your e-commerce site is processing a credit card transaction. Your Web site should inform the customer that the transaction is being processed.

Most Web sites do warn users that it may take 30-45 seconds to process their credit card, before they submit their order. I recommend that you take this one step further.

For example, you could display a small animated hour-glass while the credit card is being processed. Yes, this is a cheap and simple trick. But it works! The user would get the impression that their transaction is being processed and the system hasn't stalled.