What is a confidence interval? I wanted to know that recently and turned to one of my favorite books: Measuring the User Experience, by Tom Tullis and Bill Albert. And here’s what they say:
“Confidence intervals are extremely valuable for any usability professional. A confidence interval is a range that estimates the true population value for a statistic.”
Then they go on to explain how you calculate a confidence interval in Excel. Which is fine, but I have to admit that I wasn’t entirely sure that once I’d calculated it, I really knew what I’d done or what it meant. So I trawled through various statistics books to gain a better understanding of confidence intervals, and this column is the result. Read More
Metrics are the signals that show whether your UX strategy is working. Using metrics is key to tracking changes over time, benchmarking against iterations of your own site or application or those of competitors, and setting targets.
Although most organizations are tracking metrics like conversion rate or engagement time, often they do not tie these metrics back to design decisions. The reason? Their metrics are too high level. A change in your conversion rate could relate to a design change, a promotion, or something that a competitor has done. Time on site could mean anything. Read More
In this installment of Ask UXmatters, our experts discuss how to write effective usability requirements and determine the right metrics for the redesign of a legacy, public-sector system.
Ask UXmatters exists to answer your questions about user experience matters. If you want to read our experts’ responses to your questions in an upcoming installment of Ask UXmatters, please send your questions to: [email protected]. Read More