LIS 504 - Scales and measures

Types of scale

Type of scale Meaningful Examples
Order of categories Distances between categories Ratios between values
Nominal No No No Subject category.
Ordinal Yes No No Maclean's rankings of university libraries.
MLIS students' ranking of electives.
Interval Yes Yes No Year a book was published.
Date a Web site was last updated.
Ratio Yes Yes Yes Number of days a book was on loan.
Number of bytes in a file.

Meaningful measures for different types of scale

Type of scale Measures of central tendency Measures of dispersion
Mean Median Mode Percentiles,
standard deviation
Concentration measures, such as Simpson's l
Nominal No No Yes No No Yes
Ordinal No Yes Yes Yes No Yes
Yes Yes Yes Yes Yes Yes


Last updated November 1, 2000.
This page maintained by Prof. Tim Craven
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Faculty of Information and Media Studies
University of Western Ontario,
London, Ontario
Canada, N6A 5B7