Utilisabilité

Utilisabilité, often referred to in the English-speaking world as usability, is a discipline within ergonomics and human‑computer interaction that focuses on the ease with which users can achieve their goals using a product or system. It encompasses the design of interfaces, the structure of information, and the overall user experience. An assessment of utilisabilité seeks to identify barriers that hinder efficient, effective, and satisfying interaction, and to propose solutions that reduce cognitive load and error.

Key principles that guide the evaluation and improvement of utilisabilité include learnability, efficiency, memorability, error prevention and recovery, and user satisfaction. These principles are often operationalised through heuristic analyses, such as Nielsen’s ten usability heuristics, and through empirical methods like usability testing, cognitive walkthroughs, and eye‑tracking studies. Useful quantitative metrics include task success rate, time on task, error frequency, and satisfaction ratings obtained through tools such as the System Usability Scale or the Norman Scale.

Historically, the term gained prominence in the 1970s and 1980s with the rise of computer­-based workstations and the need for user‑friendly interfaces. Since then, utilisabilité has expanded beyond software to cover digital products, websites, mobile apps, and even physical devices. Modern practices integrate usability considerations with broader user experience (UX) design, emphasising iterative design, participatory testing, accessibility, and context of use. By prioritising utilisabilité, designers and organisations can improve product quality, reduce support costs, and increase customer loyalty.