Title: Ordinal
Course: UGQuants (SSPS) > Section: Introduction to Quantitative Analysis

Ordinal

With an ordinal level of measurement, the values of a variable are not only distinct from one another, they also have a logical order to them in which each value can be described as higher and/or lower than another. Another way to think of this is that the values have an obvious ‘rank’ order. For example, a variable that records someone’s highest educational qualification might have values that run from the highest (e.g. a university degree) to lowest (no qualifications). General level of interest in politics might have values ranging from ‘very interested’ to ‘not at all interested’. Or self-rated health might be measured from ‘very good’ to ‘very poor’.

In each of these examples we can say that someone in one category is more or less highly qualified than someone in another category; or has more or less interest in politics; or has better or poorer self-rated health. So the numerical values are meaningful: e.g. if for highest educational qualification we assign the value 1 to cases with a university degree and the value 5 to cases with no qualifications then we can say that a case with a value of 3 is more highly qualified than a case with a value of 5, but less so than a case with a value of 1. However,  we cannot say is that the difference in education between cases with values 3 and 1 is exactly the same as the difference between values 3 and 5, or indeed that a case with a value of 5 is ‘five times less qualified’ than a case with a value of 1. To put it another way, the values have a rank order but there is not a meaningful arithmetic difference between values.

Links
Self-completion questionnaire: youth self-completion questionnaire of the 2012 wave of ‘Understanding Society’, the UK Household Longitudinal Study Q13 to Q15 | Questionnaire filled out by interviewer: Survey of Carers in Households 2009/10 - No. 3a | Questionnaire filled out by interviewer: Scottish Social Attitudes Survey 2010 Q262 on page 25