Counts, scales, and scores. Levels of observation
G. W. Brown
Description, analysis, and interpretation of biomedical information are
guided, in part, by the nature of the observations. Objects or events in
categories, ie, nominal data, are simply counted. At a somewhat higher
level, observations may have a "more than" character, so they can be
ordered or ranked; the increments between the elements may be unknown or
not measurable. Interval data have known and fixed increments, but no true
zero; ratio scales are interval observations with a true zero. Some
relationships between the levels of observation and the presentation and
interpretation of biomedical information are discussed.
