What does "effectiveness" indicate in usability principles?

Effectiveness in usability principles refers to the degree to which users can successfully achieve their goals using a system. This means that it emphasizes how well the system performs the tasks that users need to complete. A reliable system that allows users to complete tasks accurately and efficiently reflects high effectiveness. It ensures that the users can rely on the system to produce the intended results.

While other aspects of usability, such as efficiency (which pertains to the speed of task completion), functionality (the number of features available), and aesthetic appeal (the attractiveness of the design), are also important, they do not directly relate to the concept of effectiveness. Focusing on effectiveness helps in assessing how well a system meets users' needs and whether they can achieve their goals without significant hindrance or error.