2. Subjective evaluation focused on difficulty of use

The techniques in this section focus solely on the subjective evaluation of a product's "difficulty of use". They are based on a body of knowledge about the mental evaluation process carried out by any user, resulting from research carried out by physiologists, psychologists and ergonomists.

These techniques fall into two categories, depending on whether they are used in predominantly physical or mental activities.

The techniques used for predominantly physical activities associate the physical difficulty perceived when using a product with the perception of effort, using an evaluation scale.

In the case of predominantly mental activities, the first technique is to guide the user towards an assessment corresponding to what he perceives. To do this, the user answers increasingly precise questions about how he feels,...