Most discussions of measurement theory are focused on "scales" of measurement, but it is not clear whether reference is made to the mechanisms of measurement or the metric information derived from measurement. This emphasis on scales in measurement theory has not always provided a meaningful or fruitful description of measurement activities in…

The term measurement has been used in a number of different sub-areas of psychology without an explicit recognition of the commonalities and potential differences in measurement characteristics. Analysis of these measurement situations reveals that the one common factor is that a mechanism or discriminative process, that is a standard system of…