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Comparability is the extent to which differences between statistics from different geographical areas, non-geographical domains, or over time, can be attributed to differences between the true values of the statistics.

In SDMX, "Comparability" is closely associated with "Coherence", which is the adequacy of statistics to be reliably combined in different ways and for various uses. The use of standard concepts, classifications and target populations promotes coherence, as does the use of common methodology across surveys. Coherence does not necessarily imply full numerical consistency.

Under the SDDS, the comparability of statistics within and across statistical frameworks - and the ability to perform cross-checks and reconciliations - requires the dissemination of components underlying aggregate series, dissemination within a statistical framework, and/or the dissemination of related data that support and encourage users' ability to check and verify the quality of data.

The sources of distortion of comparability in statistics, increasing or reducing it, are mainly twofold:

- use of different concepts/definitions, or

- use of different measuring tools, compilation and presentation practices.

Statistical Data and Metadata Exchange (SDMX) - BIS, ECB, Eurostat, IBRD, IMF, OECD and UNSD - Metadata Common Vocabulary

In the context of PPPs comparability refers to the requirement that countries price products that are identical or, if not identical, equivalent.

Products are said to be comparable if they have identical or equivalent physical and economic characteristics – that is, if they have the same or similar technical parameters and price determining properties. In this context, equivalence or similarity between products is defined as meeting the same needs with equal efficiency so that purchasers are indifferent between them and are not prepared to pay more for one than for the other.

The pricing of comparable products ensures that the differences in prices between countries for a product reflect “pure” price differences and are not affected by differences in quality. If the requirement is not respected, differences in quality will be mistaken for price differences leading to an underestimation or overestimation of price levels and a corresponding overestimation and underestimation of volume levels.

Eurostat, OECD, 2007, Eurostat-OECD Methodological Manual on Purchasing Power Parities, OECD, Paris – Annex VII, Glossary of terms and abbreviations.

Source Publication:
Statistical Data and Metadata Exchange (SDMX) - BIS, ECB, Eurostat, IBRD, IMF, OECD and UNSD - Metadata Common Vocabulary.

Cross References:
Quality – Eurostat
Quality - ISO
Special Data Dissemination Standard (SDDS)
Statistical Data and Metadata Exchange (SDMX)

Statistical Theme: Quality, statistical

Glossary Output Segments:

Created on Tuesday, September 25, 2001

Last updated on Thursday, July 12, 2007