1. Define your users and identify their capabilities

Depending on the products you design, your potential users may vary. Some products are potentially aimed at everyone (e.g. a cell phone), while others concern a more restricted population. For example, a car's driving position does not need to be adapted to the characteristics of children or blind people, as they are not allowed to drive. Another example: a work tool does not need to be adapted to the characteristics of children or the elderly, as they are not expected to be in a work situation. However, it may concern a disabled employee.

Once users have been identified, the capabilities we are interested in are those involved in interacting with a product:

• Sensory capabilities: hearing, touch and vision impairments, color blindness, etc. For example, the standard use of a cell phone requires visual skills (reading...