Statistics Finland's Classification Services maintain and publish national classification recommendations. Several of them are based on international standards confirmed by EU directives. Use of classification recommendations improves the comparability of statistical information produced at different times and in different areas.

Classifications consist of headings, or names of groups, of codes given to them, i.e. numerical or alphabetical codes, and of descriptions of groups, i.e. definitions. Classification refers to dividing individual items of information present in statistical data according to certain features into different groups where each unit belongs to only one group. In the classification the groups are named and codes are issued to them.

Classifications can be divided into four groups: