A Summary of Measurement Scales, Their Characteristics, and Their Statistical Implications

Nominal
A scale in which the numbers serve as labels rather than have numeric value (i.e., 1=male; 2=female). Can be used for determining the mode, the percentage values, or the chi square.

Ordinal Scale
A scale which "measures" in terms of such values as "more" or "less," "larger" or "smaller," but without specifying the size of the intervals (i.e., 78 %iles). Can be used for determining the mode, percentage, chi square, median, percentile rank, or rank correlation.

Interval Scale
A scale which measures in terms of equal intervals or degrees of difference, but whose zero point, or point of beginning is arbitrarily established (i.e., 32 degree Fahrenheit). Can be used for determining the mode, the mean, the standard deviation, the t-test, the F test, and the product moment correlation.

Ratio Scale
A scale which measures in terms of equal intervals and an absolute zero point of origin (72 inches tall). Can be used for determining the geometric mean, the harmonic mean, the percent variation and all other statistical determinations.

Del Siegle, Ph.D.
Neag School of Education - University of Connecticut
del.siegle@uconn.edu

www.delsiegle.com