Is there a quantitative measure for usability?

Someone asked me the other day if there was a¬†quantitative¬†measure for usability. Me, being a person who doesn’t lack an opinion, laid out my philosophy. Thought it would be useful to post this to my blog as well, in case anyone else was interested in my answer.

Usability is measurable. If tested, usability needs to be measurable. It’s about task completion, steps to success, faults in the process, number of clicks/taps to get to success. We can take a design, assess its usability, take a competing design solving same task, assess its usability, and compare. A is more usable than B. It’s pure metrics and HCI.

Where things get tricky is if we talk about measuring user experience. That is not measurable because user experience is through the lens of the person using it and leans heavily on variables like history, perception, and emotion (to name a few). Continue reading