Comparability

Comparability - geographical

The production of producer and import price indices is an obligation by all EU Member States under the guidelines set out in Council Regulation (EC) No 1165/98 of 19 May 1998 on short term statistics.

The statistics can thus be compared internationally via Eurostat, where data from the various EU member states are available.

The statistics are internationally known by the abbreviation PPI and also produced outside the European Union.

Comparability over time

These statistics have been produced in its current form since 2000, but changes in the year of comparison, the base year and the industry classification have occurred during that period.

• From 2005 to 2008, 2000=100, weight year is 2000 and industry classification is DB03
• From 2009 to 2013, 2005=100, weight year is 2005 and industry classification is DB07
• From 2014 to 2018, 2010=100, weight year is 2010 and industry classification is DB07
• In 2019, 2005=100, weight year is 2015 and industry classification is DB07
• In 2020, 2015=100, weight year is 2016 and industry classification is DB07
• In 2021, 2015=100, weight year is 2017 and industry classification is DB07

To enable comparisons with earlier periods it is, in principle, possible to interlink old and new indices by comparing indices with new and old year of comparison for the same period

When comparing indices over a longer period of time it is important to note that weight changes and the continuous update to the sample interferes with the assumption of a fixed basket of goods, central to price index theory. Though these measures are taken to ensure the index better reflect the current turnover in the Danish economy.

The Price index for domestic supply have been produced in its current form as a monthly index since 1981, but have changed base and weight reference year during the period.

The Price index for domestic supply is also published as a yearly index in the StatBank, PRIS1900. Statistics Denmark have produced different version of the index since 1876, and first published the index in Statistisk årbog fra 1913 (tabel 61). The index has had different names through the years but became the Price index for domestic supply in 2003. The yearly index published in the StatBank is an index compiled from a series of indices from 1876 and up to today, and these indices have had different methodological changes through the years, which is something to note when using the index.

The Price index for domestic supply has had a number of changes from its inception until now. Immediately below is a structured overview of the changes to base year, weight reference year and commodity groupings: -Period: 1925-1934. Base year: 1913=100. Weight year: 1924. Commodity grouping: 11 Groups. -Period: 1935-1937. Base year: 1931=100. Weight year: 1934. Commodity grouping: 11 Groups. -Period: 1938-1956. Base year: 1935=100. Weight year: 1935. Commodity grouping: 11 Groups. -Period: 1957-1971. Base year: 1955=100. Weight year: 1954. Commodity grouping: SITC. -Period: 1971-1981. Base year: 1968=100. Weight year: 1966. Commodity grouping: BTN. -Period: 1982-1984. Base year: 1975=100. Weight year: 1975. Commodity grouping: CCCN. -Period: 1985-1993. Base year: 1980=100. Weight year: 1980. Commodity grouping: CCCN. -Period: 1994-2002. Base year: 1990=100. Weight year: 1990. Commodity grouping: HS. -Period: 2003-2004. Base year: 2000=100. Weight year: 1998. Commodity grouping: HS. -Period: 2005-2008. Base year: 2000=100. Weight year: 2000. Commodity grouping: HS. -Period: 2009-2013. Base year: 2005=100. Weight year: 2005. Commodity grouping: HS. -Period: 2014-2018. Base year: 2010=100. Weight year: 2010. Commodity grouping: HS. -Period: 2019. Base year: 2015=100. Weight year: 2015. Commodity grouping: HS. -Period: 2020. Base year: 2015=100. Weight year: 2016. Commodity grouping: HS. -Period: 2021. Base year: 2015=100. Weight year: 2017. Commodity grouping: HS.

The index was originally calculated on the base of the utilized prices for 38 significant commodities in the valuation calculations in the trade statistic, and further added weight after significance. Through the years the sample have been expanded upon and different methodologies, price definitions etc. have been introduced. Immediately below is an overview of these changes, but if you want to know more you can find a more detailed overview in a document on our subject page in the near future.

Overview of changes through the years: -1913: The index was published for the first time in Statistisk årbog 1913 for the years 1876, 1881, 1886, 1900, 1901, 1905, 1906, 1907, 1908, 1909, 1910, 1911 and 1912. -1914: The total index series from 1876-1913 is published for the first time in the Statistisk årbog 1914. As base year for the index the average of 1891-1900 is set to 100. -1925: The department of Statistics reorganizes the statistic from a yearly to a monthly index. -1936: Increased price information and new groupings. -1957: The statistic changes name from The wholesale price number to The wholesale Price index, roughly translated from Danish. An English version of the index was not published at the time. -1963: The price definition changes from whole sale prices to producer prices. -1982: The raw material price index is included independently in the import table. -1985: New price information and weights. Price reference and base year are changed to 1980=100. -1994: The weights and price information are revised. Base year is changed to 1990=100 and the utilized nomenclature is changed to HS (Harmonized System). -2001: The data of price collection is change from the 25th to the 15th in the given month. -2003: The calculation methodology changes from a simple arithmetic average to a geometric average and the price definition is changed to transaction prices. The index changes name to The price index for domestic supply. -2004: The price definition for import prices is changed from sales price to purchase price. -2013: The overall statistic has a name change to The Producer- and Import price index for commodities. The price index for domestic supply continues to be produced under this new overall name for the statistic. The raw material price index is discontinued.

A lot of these cases constitute a structural break in the data. Furthermore, there a changes to nomenclatures, weights, the basket of goods, groupings, and collection methods. It is important to note all of these when utilizing the yearly Price index for domestic supply that is compiled by historical indices.

Coherence - cross domain

The statistics are related to the Producer price index for services, which, like Producer and Import price index for commodities, are used for fixed price calculations in the calculation of Denmark's national accounts.

The producer price indices for goods and services highlight the price development in the first turnover stage (business-to-business), as opposed to Consumer price indices, which highlight the price development of the goods and services included in household consumption.

The statistics are harmonized with the national accounts by virtue of the weights used, based on their product balances. The producer price indices are an integral part of the fixed price calculations in the national accounts, which allow the calculation of volume changes in the Danish economy.

Coherence - internal

Price indices by industry groups and commodity group are calculated on the basis of the same data.

The calculation of the price index is based on the price change for the individual product in the sample. Therefore the composition of products in a commodity group can have different quantities and units of quantity. For example if the price for a 500 gram steel bolt is increased by 4 percent and a 1 kg steel bolt is increased by 6 percent. the average price change is calculated to 5 percent. for the commodity, steel bolts.