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Accounting Conventions


Valuation: Foreign trade figures are published as "statistical value". Value does not include any tax.

All goods covered in international merchandise trade statistics, whether sold, exchanged or provided without payment, must have a statistical value. Value of a product is the transaction value that the price actually paid or payable for goods including some adjustments in accordance with the WTO Agreement on Customs Valuation.
The valuation of goods is FOB for export and CIF for import.
Foreign trade data is available as US Dollar, Euro and Turkish Lira.
For converting currencies, daily exchange rates published by the Central Bank of the Republic of Turkey are used.

Quantity: Except natural gas and electricity, net mass is available for all the goods. Some goods have supplementary units since they have different characteristics. Which goods will be compiled according to  which quantity type is published in the Customs Tariff  Statistical Position Handbook prepared by the Ministry of Trade came into force with the Decision of the Presidency of the Republic of Turkey and publishing in the Official Gazette.

An overall measure of unit value and volume changes of exported and imported goods. 

Calculated indices;

 a) Unit value index
b) Volume index
c) Terms of trade index
d) Value index

 Value index: The index measures changes of imports and exports value by base year value. Value indices are solely calculated as an input for the volume indices and are not published.


Unit value index: Unit value index is the measure of change in the level of export or import unit values.


Quantity index: Quantity index measures the volume of external trade under the assumption that the price levels are constant.


Terms of trade index: Terms of trade is the ratio of export unit value index to import unit. If the terms of trade index number increases, it is described as a favorable movement (a unit of exports will buy more imports). If the terms of trade index number decreases, it is described as a worsening or deterioration of the terms of trade (a unit of exports will buy fewer imports).

Fisher formula, geometric mean of Laspeyres and Paasche, is used for the foreign trade unit value indices with the base year 2010. The value indices are obtained as the ratio of current values to the arithmetic average of the base year values. The volume indices are produced as the ratio of the value indices to the fisher unit value indices.

Scope of the Data



 - Normal export and import procedures
- Under customs inward and outward   processing procedures
- Border trade
- Imports by financial leasing
- Non-monetary gold
- Re-export/re-import
- Returned goods

 Items excluded from foreign trade statistics are:

- Transit trade

- Shuttle trade

- Temporary import and export

- Commodities not crossed border

- Transactions under 100 US Dollars

- Monetary gold, means of payment which are legal tender, securities (HS 710820, 4907)

- Goods for repair and maintenance

- Goods imported / exported by operational leasing

- Goods sent abroad for military troops

Analytical Framework, Concepts, Definitions, and Classifications

Foreign trade indices are calculated by using monthly foreign trade statistics.
Foreign trade statistics covers cross border trade in goods between Turkey and other countries. International trade in services statistics are not covered in statistics.
The “Special trade system” (STS) and "General trade system" (GTS) rules are applied both for production of foreign trade statistics.
Free zones and customs warehouses are not included in foreign trade statistics in the STS, on the other hand, only the goods entered or left a country’s free circulation area is included.
The general trade system (GTS) covers all goods enter the country's economic area and goods leave from country's economic area. Thus, customs warehouses and free zones in Turkey data is included in trade statistics. 
Calculation and publication of foreign trade indices will be continued by using foreign trade data according to the special trade system.
Geographical coverage: Geographical coverage is based on customs boundaries. Statistical territory corresponds to the custom territories.
Classifications: Indices are calculated according to SITC Rev.3, BEC, ISIC Rev.3  and  ISIC Rev.4. 
Indices are published by SITC Rev.3 classification in the news release.
Statistical threshold: Statistical threshold used by TurkStat in trade in goods statistics is 100 US Dollars. Transactions under 100 US Dollars are not included in trade in goods statistics.


Characteristics of Basic Data Sources

Data sources: Main data source is customs declarations. In addition, data of natural gas and electricity imported/exported by public authorities are compiled from related companies. Data of financial leasing are obtained from The Association of Financial Leasing, Factoring and Financing Companies.

Time of recording: Time of recording of export and import is either date which goods cross border (in other words date of customs clearance).

Commodity code: For compilation foreign trade data, 12-digit GTİP codes are used.

Compilation Practices

Data compilation: Customs declarations used for production of foreign trade statistics are compiled by the Ministry of Trade.

Data compilation system: The program BILGE  and Electronic Data Interchange (EDI) are used by the Ministry of Trade to compile foreign trade data.

Data processing system: Turkey's foreign trade data are processed by using SAS programme by TurkStat.

Other subjects

Periodicity: Foreign trade indices are published monthly.

Timeliness: Timeliness of statistics is compliant with the EU's and other international standards. Publication date is announced to the public with National Data Release Calendar.

Publication and dissemination: Monthly foreign trade indices are published 40 days after the referance month.

The National Data Release Calendar for following year is published in the TurkStat web site in December.

The data is disseminated simultaneously to all interested parties through the Central Dissemination Database (MEDAS) and statistical tables.

 Confidentiality: According to the Statistics Law of Turkey No: 5429

(1) Foreign trade statistics are published by TurkStat.

(2) TurkStat is authorized in determination of methods and calendar of publication of statistics.

(3) Data is collected for statistical purposes and “passive confidentiality” is used.

According to the Article 13 of Turkish Statistical Law, confidential data can be accessed only by the ones involved in the production of official statistics, to the extent that they need for performing their duties properly. If the number of the statistical unit in any cell of the data table formed by aggregating the individual data is less than three or one or two of the statistical units are dominant even if the number of units is three or more, the data in the concerned cell is considered confidential.

The  confidential  data  compiled,  processed  and  preserved  for  the  production  of  official  statistics  cannot  be delivered  to  any  administrative,  judiciary  or  military  authority  or  person,  can  not  be  used  for  purposes  other  than statistics or as an instrument of proof. Civil servants and other staff in charge of compiling and processing these data are obliged to comply with this rule. This obligation continues after the related personnel leave their duties and posts.

The rulers of the institutions and organisations producing official statistics shall take all measures to prevent any illicit access, use or revelation of the confidential data.

Data or information obtained from sources that are open to all people shall not be deemed confidential.

Data  confidentiality  ceases  when  a  statistical  unit  gives  written  approval  for  the  revelation  of  confidential data concerning itself.

Confidential data can be published only as combined with other data so as not to allow any direct or indirect identification.

(Additional clause: 25/11/2008-5813/2 article)

For the data considered confidential due to the indirect identification in foreign trade  statistics, these confidentiality rules are implemented when a statistical unit applies with a written application requiring consideration of its data as confidential.

In principle, suppressions made on commodity code. If this application isn't enough, net mass, partner country, customs can be suppressed. 

Identification of internal access to data before release: Before publishing, access to the data is prevented to everybody except staff  that work for producing foreign trade indices.

International methods: Foreign trade indices are produced in harmony with United Nations' and Eurostat's definitions, concepts and methods.

Identification of commentary on the occasion of statistical releases: Brief comments regarding data is made in news bulletin, otherwise the real interpretation of data is left to users.

Provision of information about revision and advance notice of major changes in methodology: Changes on coverage and methods before publication are shared with public, in addition that metadata is revised.

Seasonal adjustments
Seasonal and calendar related effects prevent observing the general tendency of data because of their temporary characteristics. Therefore, identification of seasonal patterns of short term indicators plays a crucial role in making reliable comparisons between consecutive periods. 

Method Used: The seasonal adjustment of External Trade Statistics is carried out using TRAMO-SEATS methodology. The software that is used for the application of this method is JDemetra+ developed by the National Bank of Belgium (NBB) in cooperation with the Deutsche Bundesbank and Eurostat in accordance with the Guidelines of the European Statistical System.

Seasonal Adjustment Process: Seasonal and calendar adjustment process of Foreign Trade Indices begins at the end of each year with the identification of the models of next year.  This specified model structure is kept fixed throughout the year to adjust seasonally and/or calendar effects. At the end of the year, just like the previous year, specification of econometric estimation models for the following year is done. The identified process repeats itself in a cyclical manner each year.
While 35 subtitles of Foreign Trade Indices contain both seasonal and calendar effects, 2 subtitles contain neither of these effects and 5 subtitles contain only calendar effects. 

Direct or Indirect Approach: Seasonally and calendar adjusted figures of Foreign Trade Indices have been produced by using direct approach independently from the seasonal adjustment of its sub-series.

Revision Policy: Seasonal adjustment procedure is subject to revisions over time because of the re-estimation of seasonal component as new observations are added. These revisions  are implemented on the data of the last three years excluding the current year.

Publication: Adjusted data can be shared publicly in  3 different ways.

  • “Calendar adjusted” data is derived from unadjusted data by removing calendar and holiday originated effects. Calendar adjusted data should be used in comparisons regarding the same month/period of the previous year.
  • “Seasonally adjusted” data is derived from unadjusted data by removing effects originating from seasonal effects. Seasonally adjusted data should be used in comparisons regarding the previous month/period.
  • If unadjusted data contains both calendar and holiday, and seasonal effects, “seasonally and calendar adjusted” data is derived by removing these effects. Seasonally and calendar adjusted data should be used in comparisons regarding the previous month/period.


Revision policy: Foreign trade statistics are revised frequently by requirements and needs.

Main reasons are; new data (customs declaration), corrections on declarations made by declarant, late answers from traders, corrections on ships and aircrafts, repair and maintenance, goods for processing, etc.

Foreign trade indices, calculated with the provisional trade data, are revised once a year for previous year, with a view to reflect updated foreign trade data effect. Indices are revised by year, months and quarters and published in january bulletin.