It is plain from this and from other statements by
the committee that the real issue is the meaning of
measurement. This, to be sure, is a semantic issue,
but one susceptible of orderly discussion. Perhaps
agreement can better be achieved if we recognize that
measurement exists in a variety of forms and that
scales of measurement fall into certain definite classes.
These classes are determined both by the empirical
operations invoked in the process of "measuring" and
'
by the formal (mathematical) properties of the scales.
Furthermore-and this is of great concern to several
of the sciences-the statistical manipulations that can
legitimately be applied to empirical data depend upon
the type of scale against which the data are ordered.