## Restoring Confidence in Usability Results

###### By Jeff Sauro, PhD . October 18, 2004 . Tags: Confidence Intervals, Statistics

Adding confidence intervals to completion rates in usability tests will temper both excessive skepticism and overstated usability findings. Confidence intervals make testing more efficient by quickly revealing unusable tasks with very small samples. Examples are detailed and downloadable calculators are available. Are you Lacking Confidence? You just finished a usability test. You had 5 participants attempt a task in a new version of