1. Why understand the actual use of your system?

This experimental approach allows you to focus your development on your target, i.e. the user of the product or service. Although iterations may seem like a substantial investment, they have been shown to cut the number of prototypes by half, the number of man-months by a quarter in the design phase and by a third in the optimization phase.

We need to remind you of a few definitions:

Acceptability is the appropriation of the object by its user.

Acceptability = Usefulness + Practicality + Price acceptability

Utility is the way in which the system will perform the required functions.

Usability is the "degree to which a product can be used, by identified users, to achieve defined goals with effectiveness, efficiency and satisfaction" (ISO 9241).

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