Restrictions on admissible changes of scale are often overlooked in science education. Ironically, this topic receives far more attention in philosophy, psychology, and sociology texts than in the natural sciences. In fact, it was the Harvard psychologist S.~S.~Stevens who introduced the now-classic taxonomy of measurement scales, classifying variables according to the transformations permitted under a change of scale. The paper below presents a brief summary of Stevens’ taxonomy and illustrates each category with examples drawn from physics. Download the PDF.
