ABSTRACT
Ergonomics is the meeting place of research traditions from different areas. Ideally, this ‘melting-pot’ of various disciplines should provide favourable circumstances for the emergence of interdisciplinarity rather than multidisciplinarity. This, however, turns out to be not always the case in the field of Ergonomics. In this respect, monodisciplinary traditions can be seen to live on in the use of criteria for outcomes of measurement, such as reproducibility, reliability and validity. Since measuring lies at the heart of science, the significance and range of measurement outcomes are a matter of obvious concern in any research area. Actually, two phenomena can be distinguished (cf. Carmines and Zeller, 1979):
• random variation in the outcomes of repeated measurements, and • systematic deviation of measurement outcomes if contrasted with external evidence.
