scale n
(in statistics and testing) the level or type of quantification produced by a
measurement. Four different scales are often used:
a A nominal (orcategorical) scaleis used to assign values to items or
individuals that belong to different groups or categories. For example,
we may assign the number “1” to all male students and “2” to all female
students in a school. But these numbers are arbitrary and interchange-
able. Thus, instead of assigning “1” to male students and “2” to female
students, we can assign “1” to female students and “2” to male students.
b An ordinal scalemakes use ofordinal numbers (e.g. first, second,
third). It ranks items or individuals in order on the basis of some
criterion. For example, based on scores on a test, test takers may be
rank-ordered as first, second or third in comparison to others who took
the same test. However, the difference between the values on the scale is
not necessarily the same. Thus, the difference in points between being
first or second on a test may not be the same as the difference between
being 21st or 22nd.
c An interval scaleis similar to an ordinal scale except that it has the addi-
tional quality that the intervals between the points on the scale are equal.
For example, the difference between a temperature of 8°C and 6°C is the
same as the difference between a temperature of 4°C and 2°C. However,
we cannot say that a temperature of 8°C is twice as hot as a temperature
of 4°C because an interval scale does not have an absolute zero.
d A ratio scaleis similar to an interval scale except that it has an absolute
zero, which enables us to compare two points on the ratio scale and make
a statement such as “This point is three times as high as that point”.
A scale for measuring height is an example of a ratio scale. Thus, we
can say that a person whose height is 220 cm is twice as tall as a person
whose height is 110 cm.
Scales can be converted into other scales. However, the direction of scale
conversion is only one-way (i.e. a ratio scale 6 an interval scale 6 an
ordinal scale 6 a nominal scale), not the other way round.
scalogram n
see implicational scaling
scanning n
(in reading) a type of reading strategywhich is used when the reader
wants to locate a particular piece of information without necessarily under-
standing the rest of a text or passage. For example, the reader may read
through a chapter of a book as rapidly as possible in order to find out
information about a particular date, such as when someone was born.
scale