ISO 9241 mentions three aspects of user-centred design: effectiveness, efficiency, and satisfaction. Which two were most often quoted?

In the context of ISO 9241 and user-centered design principles, the two aspects that are most often quoted are effectiveness and efficiency.

1. Effectiveness refers to the accuracy and completeness with which users achieve specified goals in a particular environment. It is about ensuring that users can complete tasks correctly and successfully.

2. Efficiency involves the resources expended in relation to the accuracy and completeness of goals achieved. This means it focuses on the speed and resource utilization required to perform tasks.

While satisfaction is also important, effectiveness and efficiency are more frequently highlighted in discussions related to the practical implementation of user-centered design principles. This focus on effectiveness and efficiency indicates a priority on achieving successful user outcomes and ensuring optimal performance in design processes.