Glossary » counterbalancing

counterbalancing

A technique in experimental design that is used to avoid the introduction of confounding variables. In usability testing, this technique is most commonly used when establishing task order.

For example, a website user test might ask participants to complete two tasks: 1. find the sitemap, 2. sign up for the email newsletter.

If the study’s 12 participants complete these tasks in the same order each time, a researcher who observes high success rates on task #2 may falsely conclude that finding the email newsletter is easier than it really is. The reality may be that success rates on task #2 were artificially inflated because participants had already learned important things about the website as they completed task #1.

Counterbalancing the task order by having 6 participants begin with task #1 and 6 participants begin with task #2 removes this potential confound.