User-Centered Design & Usability Testing
Usability testing fits in as one part of the user-centered design process. In a usability test, representative users try to find information (or use functionality) on the Web site, while observers, including the development staff, watch, listen, and take notes. The purpose of a usability test is to identify areas where users struggle with the site and make recommendations for improvement.
Usability testing is typically best implemented after you've completed earlier steps in the UCD process. It's better to clearly define problems, goals, and objectives before testing your site.
User-Centered Design vs. Testing
UCD, sometimes called usability engineering, is a structured approach to producing a Web site that involves users throughout the entire design process to create a Web site that works. UCD involves several methods, each applied at appropriate times, including:
- defining business and user goals and objectives
- gathering requirements
- evaluating design alternatives, building and testing prototypes
- analyzing usability problems, testing a site with users, and proposing solutions to problems
Benefits Outweigh Costs - Iterative Testing
You can use usability testing to show that the benefits of usability engineering outweigh the costs. The types of problems that you might find costing time (and therefore money) are misleading navigational cues, poorly designed pathways, pages that are so dense they take a long time to use, etc.
Here is how you can use usability testing to show how benefits outweigh costs:
- Conduct a usability test on an early version of the Web site (or other product). This could be the old site or one done without involvement of usability specialists. Have actual users try to complete relevant tasks, measure completion rates and the time to complete the tasks.
- Identify and fix problems.
- Conduct a usability test on the new version of the site. Try to match user demographics from the first test, use the same tasks and measure completion rates and time.
- Calculate the improvement in average time to complete each task and completion rates. You can do the next steps for each task separately, for just one major task, or for all the tasks together.
- Multiply the time saved by the number of people who are likely to do that task in a given time period (say, each day).
If users are likely to do a task several times a day, you can also multiply by that number.
- If you have noted the time saved in seconds or minutes, convert it to hours because you will want to work in hours in the next step.
- Convert time to dollars by multiplying time saved (in hours) by users' salary (per hour).
- Find the one-year savings by multiplying your previous figure by the number of days in the year that users are likely to do the task. If this is a work task, use the number of days in the organization's working year.
- You now have the total annual savings of your usability changes - all due to time saved by fixing the product so users can do tasks more quickly.