How do correspondence tables cover other classifications?

Correspondence tables cover other classifications by showing the relationship between all positions of the two classifications involved. Eurostat states that type on its correspondence tables page, as the second of the two types of table, distinct from tables between versions of the same classification. A table between NACE and another classification in that system shows how positions in one system correspond to positions in the other, where the systems have different purposes, structures, and levels of detail.

How does NACE relate to ISIC in the tables?

The background article states the relationship in the same terms: NACE is derived from ISIC, in the sense that it is more detailed than ISIC, ISIC and NACE have exactly the same items at the highest levels, while NACE is typically more detailed at lower levels, and the definitions and guidelines for NACE are consistent with those published in the introduction to ISIC, to ensure international comparability. A correspondence table between NACE and ISIC therefore shows, at the higher levels, identity, and at the lower levels, subdivision: one ISIC group or class corresponding to several NACE groups or classes. The table does not show a version change. It shows a difference in detail between two classifications that are designed to be comparable, with NACE as the more detailed European version of the international reference.

Classification pair	Relationship stated in the manual
NACE and ISIC	NACE derived from ISIC, identical at section and division level, more detailed at group and class level
NACE and CPA	CPA structure parallel to NACE to class level, product categories assigned to one NACE activity
NACE and PRODCOM	PRODCOM headings linked through CPA, first four digits corresponding to a NACE code
NACE and MIGs	MIGs group industrial NACE activities into five demand based categories, shown by a correspondence table

How does NACE relate to product classifications?

Product classifications, such as the Classification of Products by Activity and PRODCOM, classify products, not activities, and their relationship to NACE is a relationship between products and the activities that produce them. The manual states that the Classification of Products by Activity is the European classification of products, designed to categorise products with common characteristics, and that each product is assigned to one single NACE activity. The linkage gives the Classification of Products by Activity a structure parallel to NACE at all levels, down to the fourth level, with specificities introduced at the fifth and sixth levels. The review of NACE rendered a review of the Classification of Products by Activity necessary, establishing version 2.2 aligned with NACE Rev. 2.1.

PRODCOM is the system for production statistics for mining, manufacturing, and materials recovery, with headings coded by an eight digit code, the first six digits of which are identical to the Classification of Products by Activity code. Through that link, PRODCOM is structurally linked with NACE, with the first four digits of each PRODCOM code corresponding to a NACE code. The Combined Nomenclature, used for foreign trade statistics, is linked indirectly: PRODCOM headings are derived from Combined Nomenclature headings, which allows comparisons between production and trade statistics, and provides an indirect link between the Combined Nomenclature and NACE. A correspondence table between NACE and a product classification therefore shows a product to activity relationship, not an activity to activity relationship, and the direction of the table must be stated: product to activity, or activity to product, are different readings.

How are Main Industrial Groupings shown?

Main Industrial Groupings are a European classification that groups, in demand based terms, all industrial activities represented in NACE into five categories: capital goods, intermediate goods, consumer durable goods, consumer non durable goods, and energy. The manual states that definition, and it states that correspondence tables are one of the ways in which special aggregations such as Main Industrial Groupings can be represented. The Eurostat correspondence tables page lists correspondence tables between Main Industrial Groupings and NACE Rev. 2.1 as the second set of tables published there. The table for Main Industrial Groupings shows membership: which NACE categories fall in each grouping category. It does not show a version change, and it does not show a product relationship. It shows an aggregation, for use in indicators such as the index of industrial production and the index of producer prices, as stated in the manual.

An aggregation table must be read as a grouping, with the grouping criterion stated. The Main Industrial Groupings criterion is demand based, grouping by the kind of product demand, rather than by production process or by output character alone. A NACE class can therefore sit in a grouping category that cuts across divisions, and the grouping total will aggregate classes from several divisions. A reader who reads the aggregation table as if it were a version table will treat the grouping as a move, and will misstate the relationship. The table type, aggregation, must be stated beside the table name, in the same way that the version type must be stated for a version table.

What do cross classification tables not do?

State the two classifications and the table type, read the relationship in the direction needed, and confirm any entry with the national statistical institute or the business register that holds the record.