What the series is for
ISO 10075 provides an ergonomic framework for discussing mental workload precisely. It is neither a single questionnaire nor a universal threshold for declaring a job safe. It separates external work demands from the immediate response they produce in a person, which depends on that person’s circumstances and resources.
The technical terms mental stress and mental strain do not mean that every demand is harmful. A task can be stimulating, excessive or insufficient. Both overload and underload therefore matter, and intellectual activity should not automatically be equated with injury or illness.
The role of each part
Part 1, ISO 10075-1:2017, defines concepts and their relationships. Part 2, ISO 10075-2:2024, addresses design principles; Spain lists its adoption as UNE-EN ISO 10075-2:2025. Part 3 addresses requirements for measurement and assessment methods. National adoption dates can differ from international publication dates.
Design covers tasks, equipment, surroundings and organisational and social factors. It also matters in predominantly physical jobs requiring monitoring or decisions. Part 2 does not replace measurement methods or, by itself, address personnel selection and training.
Applying it to a real job
Before choosing a tool, describe the information people receive, the decisions they make and the time available. A display containing numerous alerts may increase information searching; monotonous monitoring may make sustained attention difficult. These are different situations requiring different interventions.
A redesign might organise alerts by relevance, clarify priorities and check whether response times are realistic. Test the modification with users and representative situations, including interruptions and periods of peak demand. The assessment should not depend solely on the designer’s impression of how easy the task appears.
Interpreting findings
Combining observation, worker participation and suitable assessment methods helps explain the demands. An individual result does not automatically identify an organisational cause and is not a medical diagnosis.
Document tasks, assessment conditions, proposed changes and subsequent checks. The series supports technical reasoning; practitioners must justify their chosen method and consult the applicable part when verifying specific requirements. Repeating a questionnaire without examining actual changes in task design would not establish that the underlying problem has been addressed.
