Surveys and Methodology

What is a classification?

A classification is an ordered set of related categories used to group data according to its similarities. It consists of codes and descriptors and allows survey responses to be put into meaningful categories in order to produce useful data.

A classification is a useful tool for anyone developing statistical surveys. It is a framework which both simplifies the topic being studied and makes it easy to categorise all data or responses received.

Features of a classification

It is generally accepted that a standard classification will usually meet a number of requirements which are outlined below.

Exhaustive categories  - All survey responses need to fit into the classification structure somewhere

Precise and meaningful descriptors for categories - The content of each category in the classification should be clearly defined

Conceptually sound - The classification should have a conceptual basis and a logical structure

Statistically balanced - In general, survey responses should not fall heavily into one category and sparsely into the other categories

Operationally feasible - There is no point in having a classification that cannot be implemented in practice

Statistically robust - The classification should be able to be used for a number of years without revision

Internationally comparable - The classification should be comparable with any international standard classification

See also the CSO Guide to Classifications (PDF 307KB)