Inside Technique : Web Site Usability
By Bill Pawlak

So you're going to build a web site, are you? You've got your drag-and-drop web-creation program all fired up, you know how to do drop shadows in Photoshop, you've got a link to both a counter and a web stats page and, as soon as you learn the languages, you're going to create the most awesome web site ever in existence, taking advantage of style sheets, frames, Java, and DHTML... Now all you need to do is make sure your web site makes the grade from a usability perspective and you're good to go.

Wait a minute? What's that? Usability? Is that some sort of new technology you need to learn? An applet you need to get?

Nope. It's more important than that stuff. It's probably the most important thing you can do for your site. In fact, it applies to almost every aspect of technology that we humans have to use.

What is Usability?

Any system's performance can be measured along a number of different dimensions. Power consumption, startup/shutdown times, error recovery capabilities, safety, and temperature accuracy are all examples of different measures that can be applied different systems. In essence, usability is simply another measure that can be used to evaluate the performance of systems.

But note that not all measures can be applied to every system. For example, it doesn't make sense to describe the performance of your toaster or software program in terms of city & highway mileage ratings. Usability, however, can be applied to virtually any system that humans have to use to get something done.

Simply put, the usability of a system is an evaluation of the interaction between the design of a system and how effectively that design helps people learn, understand, operate, and remember what they need to in order to use the system to accomplish their goals. It combines both objective and subjective measures, which I'll describe in more detail a bit later, and it applies to everything from an Air Traffic Control system to your VCR to your software to your website.

For example, did you know that your toaster can be evaluated for its usability?

Although it's not really a complex system and the goals of using a toaster are relatively straightforward, you can evaluate how easy it is to operate the toaster to make toast (one possible goal you might have when using a toaster). Take a minute to think about the answers to these questions: Can you understand how to operate the controls? Do you know what effect each temperature setting will have on your bread (i.e., what's the difference between "yellow" and "brown")? Do you know what to do if there's a problem and your toast doesn't "pop up?" (Hint: Don't stick a fork in it and try to pry the toast out!)

Usability for More Complex Human-Machine Systems

Although we can evaluate the usability of a toaster, the real benefit of good usability is seen in more complex sytems. For example, let's consider the usability of a software application used to install virus protection software on your computer. Here are some examples of how we might evaluate the usability of this type of system:

• Is the software easy to learn or must you bury yourself in an 80 page manual before you can get started?
• Do you understand the terminology being used?
• How quickly can you accomplish the task?
• Do you know what's going to happen (what's really going to happen) to the files on your computer when you install the software?
• Is there a consistent set of buttons and menus available so that you can navigate through the program fairly easily?
• How well does the program keep you from getting lost in the process?
• From erasing everything on your hard drive?
• Can you read the text on the screen with your current monitor setting?

The list of issues goes on and on and if you don't address them, your system could be a failure. Why? Read on...

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