Describing, Clarifying and Presenting Data

2. Characteristic, Variable and Measurement

In Module 1, a variable was defined as the measurement of a certain characteristic that varies between members/units of a population.

Understanding the relationship between characteristic and variable is important for you to understand how good the data are. Consider, for example, a newspaper article on child poverty in which the heading claims, ‘Our children are fifth poorest’ [1]. One of your first questions should be: “How is ‘child poverty’ defined for these data?” From the information available in the article, it seems to you as though the definition of poverty was based on the variable of parental wages. This would seem to indicate that no attempt was made to measure cost of living outside of wages as an indicator of child poverty. What about other important variables, like the availability of resources such as telephone access and availability of transport? Should such variables have been considered in the assessment of child poverty? Can income alone be considered a good variable for measuring child poverty?

Thinking critically about how a characteristic is defined and measured by a variable is an important step towards becoming statistically literate. Let’s begin by looking closely at the relationship between characteristic and variable.

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