Usability

Usability describes how well users can operate a digital product to reach a specific goal. The international standard ISO 9241 defines the dimensions effectiveness, efficiency and satisfaction. Effectiveness asks whether the goal is reached at all, efficiency at what cost, and satisfaction how pleasant the journey was.

Difference from user experience

Usability is not identical to user experience, it is a subset of it. While usability measures pure operability, user experience also covers emotional factors like trust, anticipation, pride or frustration. A site can be highly usable technically and still produce bad experiences when, for example, the brand tone is off putting or the visual style is unappealing.

How usability can be measured

Common methods include moderated user testing, where real people complete tasks on a prototype, supplemented by heuristic evaluation against Nielsen's ten heuristics. Quantitative measures include success rate, time on task, number of error attempts and questionnaires such as the System Usability Scale. A small group of five to seven test participants per variant typically surfaces the majority of all significant issues.

In everyday marketing

Poor landing page usability shows up as high bounce rate, low dwell time and form completion errors. Before every campaign, the landing page should therefore be tested against typical tasks, not just after launch. Email templates also benefit from testing, for example for long buttons, small tap targets or hidden unsubscribe links that are legally mandatory but often deliberately hard to find.