Levels of Measurement

Levels of Measurement

Nominal level of measurement is not much of a number in mathematical sense. For example, a social researcher assigning a 'number one' to males and 'number two' to females, is using these numbers to distinguish the gender, but the numbers have no mathematical implication. 'Number two' in this type of measurement is not higher than 'number one', nor, is it in any sense twice of the quality of gender when compared to 'number one'. The numbers are used as names of categories, much like, the numbers on the identity cards. Another familiar example of assigning numbers to the various religions is as follows: Muslim - 1, Christian - 2, Hindu - 3, Buddhist - 4, Sikh - 5, Jain - 6 and Zoroastrians - 7. Note that these numbers do not reflect either order or magnitude. They are codes for the computers to understand the different religious affiliations. From this it is also clear that one cannot use any mathematical operation like addition, subtraction, division or multiplication. Nor can we compute the average and other such statistics. For example, it does not convey any meaning to find the average of the score one and two in the above stated gender scale. Nominal level is the lowest level of measurement.

In the ordinal level of measurement, assigned values do reflect an order. Take for example, the students of a class of sixty are made to stand in a line according to their heights and each one is given a number from 'number one' to 'number sixty' according to the order in which they are standing. In this scheme 'number two' is higher than 'number one' and 'number three' is higher than 'number one' and 'number two', because the student represented by 'number two' is certainly taller than the student who has received 'number one'. Thus, the scores from one to sixty represent the natural order of the students' height.