by JESSICA MILLER 6, Nov. 2013
One of the bigger problems that designers and testers have in the way of usability is in working out a really good way to not only accurately measure it, but to implement standards for good and bad when it comes to the metric you get. In the past, many people have worked out their on guidelines and measurement systems, and this has resulted in, when case studies and published materials are released, a lot of confusion, and it makes usability difficult to actually measure. However, with the advent of the system usability scale (SUS), this isn’t nearly the problem it used to be.
The system usability scale is a series of ten questions with degree- based answers, one for strongly disagree, five for strongly agree. After the questions are answered, the numbers are tallied (and multiplied by 2.5) for an overall score. Now, fortunately, there is more or less a consensus on what a good score, when using the SUS, might be. A 68 is considered very good, and some variance in either direction is to be expected. So, the SUS is a very good, easy to use and pretty unanimously accepted scale to measure usability. That makes this all much less of a hassle. Well, this wasn’t that time consuming to explain, so let’s take some of the extra time we have, to talk about the questions commonly asked in the SUS. [Article]