1) What is usability?
Usability is all about how easy a product, service or system is to use. The international standard ISO 9241-11 provides guidelines for usability and define it as:
The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.
We can find three important aspects of usability:
- Effectiveness: Can the users achieve what they want by using the system?
- Efficiency: How much resources (for example time) are needed?
- Satisfaction: What do the users think of their interaction with the system?
But these aspects are affected by:
- The users: Who uses the system? Are they highly trained and experienced users, or novices?
- Their goals: What are the users trying to do with the system? Does it support what they want to do with it?
- The user situation (or context): Where and how is the system used?
Usability should not be mixed up with functionality which refers to the system's functions and does not take into consideration whether the user can use them or not. More functionality does not mean higher usability!