The reasoning behind the development of a series of standards specifically addressing mental workload is partly that this workload is associated with consequences of strain (such as monotony) and means of measurement (such as interviews, observation, etc.) that differ from those for physical work requirements. The three parts of EN ISO 10075 provide orientation regarding key terms and principles for the design of work and for requirements concerning measurement methods.
Since standards must take account of the general consensus between experts regarding the latest observations and knowledge, they are reviewed at regular intervals. This was the reason for addition of the essential terms and concepts during revision of EN ISO 10075-1 (Ergonomic principles related to mental workload – Part 1: General issues and concepts, terms and definitions). The basic concept remained unchanged, namely the distinction between stress – the term for all external influences acting upon a human being, and strain – the term for the impact upon the individual as a function of his or her particular characteristics, abilities, skills, etc.
The differentiation between facilitating and impairing consequences of strain was also retained. Potential long-term effects of this strain are now also considered however, namely competence development and burnout as facilitating and impairing consequences respectively. The stress response was added to the impairing effects resulting from short-term exposure. The publication of EN ISO 10075-1 at the end of 2017 resulted in the preceding version, published in 2000, being withdrawn, together with DIN SPEC 33418:2014-03, which was available only in German-speaking countries.
The amendments to the first part of the standard resulted in a need for the design principles described in EN ISO 10075-2 (Ergonomic principles related to mental workload – Part 2: Design principles) to be adapted. In order to determine the need for revision, a workshop was held at DIN in December 2018 during which the viewpoint of representatives from the field was reported, beginning with (a) design approaches in the services sector/knowledge work in the banking sector, (b) working conditions and mental stress in nursing and geriatric care, and (c) experience and design strategies in the commercial sector. This was followed by discussion from a sociological perspective of changes in the world of work, which was intended to yield relevant information on possible future developments for use during the revision. With reference to the areas already presented, the workshop participants then discussed which of the design principles described in the current version of EN ISO 10075-2 are still relevant to action, which should be amended, and which could be deleted. The information obtained and proposals made in this way constitute an important basis for the revision of the standard.
A broad spectrum of methods are available for measuring mental strain. These methods differ in the manner by which data are recorded (e.g. observation, interviews, physiological measurement), the area in which they are applied (sectors, hierarchical levels in organizations, vocational groups, task classes), and in their respective theoretical underpinnings. EN ISO 10075-3 (Ergonomic principles related to mental workload – Part 3: Principles and requirements concerning methods for measuring and assessing mental workload) defines the criteria relevant to assessment of the measurement characteristics of instruments (reliability, validity, objectivity, etc.). The level to be attained depends upon the respective purpose of the measurement. The highest requirements apply when reliable and valid data are desired, for example for planned measures for work design, i.e. when a precision measurement is intended. Conversely, if an overview (screening) is required in order for problem areas associated with stresses to be identified, a moderate degree of precision is sufficient. Where an initial, general overview of the workload and strain arising is to be obtained with little effort, methods of low precision are sufficient. The standard also states the information that must be documented during development of a method and the data that must be recorded in the measurement protocol.
The procedure selected during amendment of the EN ISO 10075 series has proved effective. The basic terms and concepts (Part 1) were first to be reviewed and revised, since the additions and amendments made in the process necessitated corresponding revisions to the design principles. Revision of Part 3 is not yet on the agenda, since revision of Part 2 must first be completed.
Professor Dr Martin Schütte