Quality description: Unit value and volume indexes of the international trade in goods (2013-)
1. Relevance of the statistical data
1.1 Data content and use of the statistics
The statistics contain both monthly data and the moving 12-month averages of the development of export and import prices, terms of trade, and volumes of exports and imports. Indexes are published separately for internal and external trade. Indexes are calculated and published using the CPA2008 product classification (Classification of Products by Activity, CPA).
Price and quality indexes form an important tool for decision-makers, planners and researchers of both the public and private sector working nationally as well as in the EU and in many international organisations.
1.2 Central concepts and classifications
Unit value indexes of international trade are extracted from material that contains the company-specific international trade data in goods classified according to the CN8 combined nomenclature of the EU. To calculate monthly unit value indexes, the statistical value of the index headings per quantity unit as indicated by the CN nomenclature is used as the price quotation at the level of businesses. Index headings at the CPA4 level (CPA 2008) are classified so that headings that are problematic in terms of index calculations are classified under the category “others”. Such headings have irregular values and include items such as combat vehicles, ships, aircraft, weapons, ammunitions and some headings classified under services. This category is different from the unspecified category used elsewhere in international trade statistics. Headings are correspondingly classified for volume indexes.
1.3 Laws and regulations
International trade statistics are based on EC legislation and on the Statistics Act (280/04) and Customs Act (304/2016) of Finland. In the EU legislation, the compilation of statistics is steered by the Basic Regulation on internal trade statistics (EC 638/2004), the Basic Regulation on external trade statistics (EC 1172/1995) and the respective implementation provisions.
The country classification is based on the Commission Regulation (EC No. 1106/2012) on the country classification of the statistics on the Community external trade and the trade between the Member States. The country codes comply with those of the ISO/DIS 3166 standard of the International Organization for Standardization.
2. Method description
The calculation of unit value indexes of international trade is based on Laspeyres’ theory, and the calculation of volume indexes is based on Paasche’s theory.
The indexes are calculated as chain indexes starting from the base year 2010, always using the year preceding the calculating year as the year of comparison.
The value weights of the calculating month are used as the weights of the unit value indexes at the micro level (CPA4).
In this formula, pit is the company’s heading-specific price of the calculating month, and qit is the corresponding volume of the calculating month. pi0 is the average of the monthly average prices (company*cn) for the year of comparison which is the preceding year.
Unit value indexes of the macro level (CPA3-CPA1) are calculated as a weighted mean based on lower-level micro indexes. The previous year’s value weights are used:
For volume indexes, value indexes are calculated first.
Volume indexes are derived from value indexes by dividing them with the unit value index:
In chaining, monthly changes in the monthly unit value indexes and value indexes are calculated, and then chained by multiplying the change of calculating month’s indexes by the corresponding variations of the previous month. For chaining at the turn of the year, December is re-calculated with the weights of the new calculating year, and the change for January is derived by comparing the January indexes with the re-calculated results for December. The resulting change is multiplied by the chained change of December.
The points of the terms of trade are calculated by using the following formula: (unit value index, exports / unit value index, imports) x 100.
The moving average is calculated backwards from the calculating month as a 12-month arithmetical average from chained unit value indexes I(Li ). The moving average of volume indexes is calculated correspondingly from volume indexes I(Pi).
New companies are included in the calculations at the CPA4 level. If the “company*cn” heading is included in the international trade statistics for two consecutive months, an artificial base year price is calculated for it: The current price of the first included month is divided by the corresponding CPA4 index:
When the CPA4 index is missing, it is replaced with the corresponding CPA3 index.
Imputation is done at the CPA3 level in the calculation of unit value indexes. Missing indexes are replaced with the corresponding index of the previous month, to which the general index changes of the current and previous month are added. In the calculation of value indexes, the 0 value is replaced with 0.1 so that the heading stays with the chaining.
In addition, the effect of the lower index heading on the general index change is calculated and published for unit value and volume indexes. Average weights weighted with the number of months have been used in the effect calculation of chain indexes where value weights vary each year. The effects are calculated with the following formula:
Wim is the average of the weights of the calculating year and of the base year of the previous year weighed with months. I(Lit) is the CPA level index of the calculating month, I(Lit-1) is the CPA level index of the corresponding month of the previous year and I(Lt-1) is the general index of the previous year.
3. Correctness and accuracy of the data
The information on Finland’s trade with other EU countries is collected from statistical declarations submitted by companies, using the Intrastat system of internal trade. Information on the goods trade between Finland and third countries is obtained from customs declarations which must be provided for all import and export consignments. The data on both internal and external trade are combined when compiling the Finnish international trade statistics.
Monthly index material is examined after the completion of the monthly international trade material. In addition, possible incorrect price data are excluded from the calculation of unit value indexes with the limit of [0,5;2]. A bigger price relationship variation [0,25;4] is allowed for oil and medicines. Index calculations are done once a month, and the figures are not updated later. The value of the final calculation material of unit value indexes covers 80 to 94 per cent of the corresponding monthly value of the international trade statistics. Monthly materials of the entire international trade are used in the calculation of volume indexes.
4. Timeliness and punctuality of the published data
Unit value and volume indexes of international trade are published within nine weeks of the end of the statistical reference month. The exact schedule of publication is defined for about a year onwards. The publishing schedule is available on the Finnish Customs website.
5. Accessibility and transparency/clarity of the data
The essential information relating to unit value and volume indexes of international trade is published on the website of Finnish Customs at times of publication announced in advance. At the same time, indexes are published extensively at the CPA1-CPA3 levels in the Uljas database.
More information on international trade statistics is available on the Finnish Customs website, under “International trade statistics”. On these pages, you find the principles of the collection of international trade statistics as well as all the statistics and surveys on Finnish international trade published by Finnish Customs.
Further information is also available from the Statistics Service at:
- telephone: +358 295 5200 (exchange) or +358 295 52335 (Statistics Service direct)
- e-mail: statistics[at]tulli.fi
- Internet: www.tulli.fi
- Statistical database Uljas: uljas.tulli.fi
6. Comparability of the statistics
Unit value and volume indexes of international trade have been produced since 1997 based on the old classifications of line of business and purpose of use. The combination of previously used index headings (CPA2002) with the new CPA2008 2-level headings has required some choices in order to find the best possible time series. Headings that correspond with each other have been chained back to the year 2002, when the CPA2002 classification was taken into use in calculation.
In import, there were 27 headings that correspond with each other. Of these, three headings (21, 23 and 31) correspond partly with each other. In export, there were 24 headings that corresponded with each other. Of these, four headings (02, 07, 21 and 28) correspond partly with each other. Below are the statistical keys used for combining headings as regards import and export:
The unit value and volume indexes of international trade have been available under the current classifications since 2010. Statistics on the international trade in goods currently use the CPA2008 classification used also for indexes.
7. Clarity and integrity/coherence
Statistical data can be found not only in the international trade statistics but also in the National Accounts and the Balance of Trade statistics of the Statistics Finland.
Statistical data on the international trade of the EU Member States are available in Eurostat’s publications, website and Easy Comext database. The database can be accessed online and it can be used free of charge. The international trade statistics compiled by the UN (Comtrade database) can be used free of charge on the UN website.
The differences in the concepts and definitions used by the EU Member States and their most important trading partners affect the comparability of statistics.