Mesurer c'est observer.

Ergonomics does not offer sustained value to the epistemological debate that has long fuelled sociology studies, such as the contradiction between quantitative and qualitative analysis in the observation of an activity. Yet many observable ergonomics, such as the subjective, emotional and the cognitive are quantifiable. The quantification of observations gives data several important features, such reproducibility and application of the same formal framework of observation in other similar situations, regardless of the observer. Objectivity leading to unambiguous identification and recognition of what will be observed, regardless of the observer. Opportunity to refute - or not - the interpretations and conclusions by examining the same corpus of collected data. Sometimes we oppose erroneously quantitative and qualitative methods. It will be shown that they complement each other in a symbiotic relationship and are not generally mutually exclusive, even if some prefer one alternative over the other or even worse, consider one as the only conceivable option to achieve the desired goal. [ABSTRACT FROM AUTHOR]