Usability goals are concerned with how useful and easy it is to use a product or system. When we design a product, we consider usability goals in order to ensure that the product delivers the expected solution to the identified problem.

here are 6 main usability goals that establish the standard:

usability goals
source: Forbes

The 6 usability goals

1. Easy to learn

2. Safe to use

3. Effective to use

4. Efficient to use

5. Good utility

6. Memorable

Usability goals must address the three usability components, i.e. effectiveness, efficiency and satisfaction. Their definition, for each of those components, must rest on the characteristics of the tasks that the tested system is supposed to support. More practically, some propose that their definition should refer to:

·        The identified end-users profiles

·        The tasks that the different categories of identified end-users are supposed to perform with the tested system in a given context of use.

·        Business goals

Moreover, for certain types of products that are used for sensitive purposes (for instance, medical devices or nuclear plant control interface), usability goals must be defined in close relation to the risk assessment process of those products. This kind of “safety-oriented usability goal” is used to prevent a tool being released on the market while identifying deficiencies in its interface design that could induce use. Thus, risks that may result in use errors must be identified; and then, for each of them, usability goals must be defined, taking into account the severity of the potential consequences of the risk (for instance, in terms of operator, patient or environment safety).

Usability goals must be included in every product design process that intends to follow a Human Factors approach (for instance, user-centred design process or Usability Engineering Lifecycle. They have to be clearly stated from the onset of the process, as soon as the end-users’ needs, risk of use, contexts and aims of use are identified.

Then, usability goals are used at each usability evaluation phase of the design process. Whatever the type of evaluation phase (i.e. formative or summative evaluation, they are used to assess the performance of the users against the result of the evaluation process:

·        During formative/constructive evaluations (i.e. evaluations that occur during the design process to contribute to further improvement of the object under evaluation, the comparison of the evaluation results against usability goals allows verifying whether those goals are met or not: as long as they are not met, the product under evaluation must be re-engineered to improve its usability. In this frame, usability goals allow also identifying usability flaws and therefore supporting this re-engineering process.

·        During summative evaluations (i.e. evaluations that try to give a definitive statement on the quality properties of a system under evaluation, the meeting of usability goals means that the system is usable enough to go out the user-centred design process and to be released.

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