A structural model of direct measurement

In the last few decades foundations of measurement have developed so as to account for both the role of\r\nmodeling in measurement, in particular relating to the presence and the effects of measurement uncertainty,\r\nand the fact that any measurement is performed by using instruments that work on the basis of\r\ntransduction effects and provide justified results only in so far as they are properly calibrated. This has\r\ntriggered a new interest about the role of instruments in the models of measurement. The structure of\r\nthe process has been variously studied in reference to the connection between measured properties\r\nand indications provided by instruments, and to the way in which intersubjective information on the\r\nmeasurand is acquired through instrument calibration. From such a background this paper proposes a\r\ncomprehensive structural model of direct measurement, whose functional elements, empirical and informational,\r\nare presented with a bottom-up strategy as a set of interrelated modules. The result, shown to\r\nbe a generalization of some of the models currently available in the literature of measurement science,\r\nhighlights the key role of scales for measurement, clarifies the conceptual and operative relations\r\nbetween direct measurement and calibration, and identifies the principal sources of measurement uncertainty\r\nin the structural context of the process. This model is intended to interpret both physical and nonphysical\r\nmeasurements, and as such it is a component of a ‘‘measurement across the sciences” research\r\nprogramme.