Beginners:Statistical concept - Classifications
This page is part of Statistics 4 beginners, a section in Statistics Explained where statistical indicators and concepts are explained in a simple way to make the world of statistics a bit easier both for pupils and students as well as for all those with an interest in statistics.
The outcome of organising information into categories according to some common characteristics is called a classification. Each category should be well-described, exhaustive and mutually exclusive. A classification usually contains codes (numbers or letters) and can be organised in a hierarchical or flat structure.
The NACE classification (abbreviation in French of La nomenclature statistique des activités économiques) is an example of a classification which is used by producers of European statistics to classify economic activities. In this way, we can for example be sure that the economic activity "manufacturing" is understood in the same way in all EU Member States and across all domains of statistics.
Examples of the most common classifications:
NACE (Statistical classification of economic activities): classification of sectors
ISCO (International Standard Classification of Occupations): classification of professions
COFOG (Classification of the Functions of Government): classification of purposes of government activities
COICOP (Classification of Individual Consumption According to Purpose): classification of purposes of household expenditure
NUTS (Nomenclature of territorial units for statistics): classification of regions
Combined nomenclature: classification of trade in goods
Why do we need classifications?
Classifications help to sort elements relating to a certain topic in a structured and hierarchical way to make sure that data collected about a topic are comparable and cover the same.
A good example is the profession “teacher”, which should be grouped in the sector “Education” and not by field of teaching subject. If not classified in a harmonized way through a classification, a teacher of mathematics might instead be counted in the sector “Scientific activities”.