Assessing Usability Part 1: Introduction

A brief introduction to the concept of usability and its importance for successful product development efforts.

This article is the first in a 4-part series on assessing usability. The current article gives a brief introduction to the concept of usability, discusses its importance for successful product development and serves as a gateway to three additional articles that deal with some methods and techniques you can use to evaluate usability. The follow-on articles are intended to give readers a general understanding of the different types of usability assessment techniques available, and to examine the strengths and weaknesses of the various methods and when they are typically employed in the product develop lifecycle.

Understanding 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. Usability can be thought of as simply another measure that can be used to evaluate performance - specifically, the performance of "human-machine" systems.

The usability of a human-machine system is an evaluation of the interaction between the design of a product and the human user of that product. It is an evaluation of how effectively the system or product design helps people learn, understand, operate, and remember what they need to in order to use the system to accomplish their goals. It concerns both objective and subjective characteristics and applies to everything from complex systems like an Air Traffic Controller's Workstation to your VCR to a website.

And even the simplest systems can be evaluated for their usability. Consider, for example, your toaster. Although it's not at all thought of as a complex system and the goals of using a toaster are relatively straightforward (heating bread enough to lightly brown it, turning it into toast), it still can have usability problems. For example, can you easily understand how to operate the controls in order to accomplish your goals? Do you know what effect each temperature setting will have on your bread (i.e., what's the difference between "yellow" and "brown" when it comes to how well done your toast is)?

Now, although we can evaluate the usability of a toaster, the benefit of having good usability is more readily seen in more complex situations.

For example, let's consider the usability of a software application used to install virus protection software on your computer. 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? 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 move 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 goes on and on...

Why is Usability Important?

It's impossible to list off of the different types of usability issues that may need to be addressed with a specific product, especially since not all measures apply to all products. But for an information system (at least for software or a website) issues such as platform compatibility, consistency, content wording, error prevention and help features, navigation, feedback, security, text readability, and the use of color all fall under the usability "umbrella" and are all fair game for a Usability Expert to evaluate.

Nevertheless, the quick list of example questions asked above should be a good indicator of why good usability is so important -- it can make the difference between a successful software install or an unwanted hard drive "cleaning," a safe plane ride or a disaster, a perfect piece of plain white toast or a char-broiled square of something that used to be Wonder Bread.

It's the difference between effectively helping users to accurately complete their tasks (and even enjoy doing so) and frustrating them because they can't do what they need to do. It affects users, developers, and managers - if you don't take care of usability, people won't buy your software, fly your plane, use your product, or surf your website.

"Ensuring" Usability

Have you ever heard of user-centered design? It's not just a buzzword, although many companies use the term without really understanding what it means. User-centered design means making sure the actual design process is rooted in providing what the user needs and wants out of the final product. It is understanding the cognitive and physical capabilities and limitations of the people who will use your product. It's designing your product to exploit what people can do well and helping them when they could use the boost. It's making sure that your end product helps people accomplish their goals and that they subjectively enjoy doing so. It's the one sure way to get people to use your product, tell their friends about it, and keep coming back to it.

Sounds like a lot, doesn't it? Well, it can be, but it's not as difficult as you may think to at least get started with user-centered design. Users are everywhere (especially if your product is a website) – all you need to do is ask them for their input.

Next Steps: Discovery

Get started on the right foot! Read Assessing Usability Part 2: Discovery for information on some techniques for effectively gathering user input at the beginning of your product design plan.

Also note that it is suggested that at least 3 different types of usability assessments are conducted on a product, preferably one from each of the three categories: discovery, inspection, and user testing. Different projects will of course have different needs and the selection of which techniques and methods to use should be based on the goals of the project.

Keep in mind that the methods for assessing usability presented in these articles are in no way a comprehensive list. Rather, it is a subset of available techniques which, for various reasons would likely provide the highest ROI for technology product development teams. Ultimately, it is simply our intent that by reading these articles, you will gain a deeper understanding of both why - and how - you should be evaluating usability as part of your product design needs.