External trade in goods, indices of volume and price

Definition of the main concepts

Price indices

The price indices are Paasche-indices.

Volume indices

The volume indices are Laspeyres-indices.

Base year and reference year

Base year: the previous year.
Current reference year: 2000.

Computation level

Price indices are estimated for all SITC commodity groups on a three-digit level (SITC- 3) based on price relatives for all representative goods for each commodity group. Goods that are not among the representative goods get the price index of their SITC-3 commodity group as an imputed price relative.

The Terms of Trade

The ratio of the price indices for exports and imports.

Definition of the main variables

Commodity

The Norwegian commodity classification for customs declarations and statistical purposes follows the international customs and statistics nomenclature (Harmonised System, HS).

Partner country

Imports: country of origin.
Exports: country of destination.

Quantity

Net mass in kilogram and, for certain commodities, quantity in supplementary units in accordance with the Norwegian customs nomenclature. To deal with commodity codes where both net mass and supplementary unit are defined, the calculation method uses a common quantity unit.

Commodity classification

The Norwegian customs' and statistical commodity nomenclature follows the HS down to the sixth digit, mainly determined by the type of material of the goods. The seventh and eighth digits are national ones, determined by customs' and statistical considerations. The nomenclature is published at the beginning of each year in the NOS Commodity List, paper edition and on the Internet: http://www.ssb.no/english/subjects/09/05/nos_com_list/ .

The United Nations' (UN) Standard International Trade Classification (SITC) by level of processing, (SITC-Rev. 4).

The NA (National Accounts) CPA (Classifications of productivity by Activity) that is used in the National accounts statistics classifies goods by sections. The (NA) CPA is based on the central product classification system of the EU (Statistical Classifications of productivity by Activity in the European Community).

Country classification

The country classification follows the international standard ISO-3166.

Name: External trade in goods, indices of volume and price
Topic: External economy

Division for Price Statistics

Indices of volume and price at country level, only.

Statistics for the 1st quarter are released 15 May or the next following working day. Statistics for the 2nd, 3rd and 4th quarter are released on the 15th or the next following working day in the month after the end of the quarter. In April/May figures for all quarters of the preceding year are released and published.

None

Series available, electronic medium or paper:
From 1880 volume indices for total imports, yearly indices, Historical Statistics
From 1919 indices for price and volume of imports and exports and by commodity groups, Historical Statistics
From 1957 quarterly indices, Monthly Bulletin of External Trade and Monthly Bulletin of Statistics

The period 1943 - 1958: monthly indices for volume in the Monthly Bulletin of Statistics and the Monthly Bulletin of External Trade 1948 - 1958

Electronic time series are available for downloading from an electronic time series reference data base which comprises quarterly series of indices for imports and exports in total except from ship and oil platforms, and commodity groups on one- and two-digit SITC-levels. Some sets of seasonally adjusted series are also available.

The purpose of the statistics is to decompose the development of the external trade with goods as measured in terms of value, into a price component and a volume component. From 1880 onwards, yearly indices for the volume of total imports were computed. Since 1919 quarterly price and volume indices by commodity group have been compiled for imports and exports.

The statistics are used in the compilation of the quarterly and yearly national accounts, as well as by the government sector, organisations, research institutions and international organisations such as the IMF.

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on ssb.no at 8 am. Prior to this, a minimum of three months' advance notice is given inthe Statistics Release Calendar.

International standard

The UN guidelines in Strategies for Price and Quantity Measurement in External Trade. Statistical Papers Series M No. 69. United Nations.

Applications under other statistical fields

The statistics are used to deflate exports and imports of goods in quarterly and yearly national accounts. The principles of the calculation of price indices for national accounts commodities are fully coordinated with the principles in the calculations of price indices for the SITC commodity groups. The calculations of price indices for national account commodities are thus based on the price relatives for all the representative commodities in the external trade within each national account commodity. The price indices for exports and imports of national account commodities are also computed as Paasche- indices with the previous year as basis. During the compilation of the national accounts the price indices for the national account commodities are being evaluated against other price statistics. As a result some of the price indices for exports and imports may be corrected before use in the national accounts. This is especially the case for national accounts' commodities within groups of machinery and means of transportation which can be weakly covered by representative goods in the external trade.

The Statistics Act §§ 2-2, 2-3 and 3-2.

No regulations in the EEA agreement.

Indices of volume and price for commodity flows between the Norwegian statistical territory and other countries (except from commodity consignments valued at less than NOK 1000 and certain types of commodity flows, for example goods under repair). The Norwegian statistical territory comprises the Norwegian customs' territory and the Norwegian part of the Continental Shelf, Svalbard, Bjørnøya and Jan Mayen.

The indices comprise customs' declared consignments and exports of crude oil and natural gas. Indices are not produced for imports and exports of ships and oil platforms, but are compiled and published by the Division of National Accounts.

The detailed database containing the individual transactions that are included in the external trade statistics, see External trade in commodities.

Use of other price indicators

There are economically important products where the external trade data do not yield any proper price information or have properties that make them unduly vulnerable in standard routines. Those shortcomings are addressed by making use of the following three categories of price information:

For commodity codes with very high value and products that are homogeneous over time, the unit price on the level of commodity code overrules any other information. This is the case for exports of e.g. crude oil and natural gas, iron and steel, certain ferro-metals, aluminium and imports and exports of electricity and some seasonal goods.

In some important products, the Norwegian data are too fragmented to yield relevant price information. To compensate for such shortcomings, the cooperation with the system of indices of producer prices has been further developed and strengthened, in that more price indexes based on direct reporting by the exporters and importers are used as indicators in the external trade statistics.

For some capital goods data from Commodity price index of first hand domestic sales (VPPI) are used.

Furthermore, the previously established practice of using price information from international commodity exchanges and foreign statistical agencies has been extended. For internationally traded commodities (refined oil products, nickel etc) price data are collected from London Stock Exchange and London Metal Exchange. For other products (especially export and import of capital goods), international price indicators are in some cases considered to be representative also for the price development of the same product group in the Norwegian trade. Price indices for the import of computers into the US published by the Bureau of Labor Statistics are in some instances used as indicators of the price development of Norwegian exports (e.g. computer equipment).

The calculations of the indices of external trade are based on the detailed database containing the individual transactions that are included in the external trade statistics. These data are supplemented by price surveys with crude oil and natural gas and electric current, in addition to international prices (already mentioned above under 3.2). Commodity codes represented by a total import or export value less than 10 million NOK are deleted from the rest of the data material; this is relevant when the total export or import value increases in year T as well.

The stratification and editing method

In order to identify the commodity codes where the data may be utilised for price statistics, the revised procedure has a first stage of two steps: stratification and control of extreme prices. See Changes in the External Trade Indices.

In the first step, data in each commodity code are stratified below the code level. The aim of the stratification is partly to arrive at more homogeneous strains within the code and, simultaneously, to reduce the overall variation observed on the code level. The stratification levels are three: Enterprise (VAT number), partner country (ISO code) and quantity groups (based on weight or supplementary unit). The choice of the best stratification variable for a commodity code in the reference year is done by means of automated analyses run on the data of the previous year (base year). This means that in the new system, the price information is collected from within the commodity codes themselves.

In the second step, before the estimation of indices, the data are run through an editing procedure controlling for extreme prices. The data are subjected to a HB (Hidrioglou-Berthelot)-based procedure for identifying extremes, both on the stratum level and within the strata. Extremes that are identified are excluded from the further use of the data.

See About the statistics: External trade in commodities.

General data editing: See About the statistics: External trade in commodities .

Seasonal adjustment of volume index series for main figures by means of the method X12-ARIMA; direct adjustment; current correction factors.

The Statistics Act § 2-6 covers the disclosure of information.

The eight-digit, HS-based commodity classification is subject to revisions due to the development of commodities in the world trade of goods. Besides, there are some national changes each year. Detailed information can be found in the annual NOS Commodity List. The most recent, major HS-revision took place at the turn of the year from 1996 to 1997 as well as from 2001 to 2002. Yearly there are also some national changes. The commodity classification by the HS was adopted in 1988 and was an extensive alteration compared to the previous nomenclature.

Customs declared commodity shipments

Collection errors may occur in the data due to misunderstandings etc., unless discovered and corrected in the customs' controls.

Exports of crude oil and natural gas

Having left the Norwegian statistical area, shipments of crude oil may be the subject of trading, and upon discharge, be redirected to a third country. In the natural gas exports, final settlements may take place at a later point in time than the compilation of the final figures of the external trade statistics.

Not relevant for the detailed custom data containing the individual transactions that are included in the external trade statistics

For the goods that are covered by price indexes based on direct reporting by the exporters and importers from the producer price index see About the statistics.

Non-sampling errors

In the case of customs declared consignments, non-sampling errors may occur by use of wrong commodity code, wrong information on quantity due to a pro-rata distribution rather than direct measurement of net mass, mistaken country codes and lack of proper information on statistical value of goods in processing trade.

The revision for the previous year is normally finished in April.