Reference metadata describe statistical concepts and methodologies used for the collection and generation of data. They provide information on data quality and, since they are strongly content-oriented, assist users in interpreting the data. Reference metadata, unlike structural metadata, can be decoupled from the data.
Short Term Statistics Department / Turnover and Volume Indicators Group
1.3. Contact name
Confidential because of GDPR
1.4. Contact person function
Confidential because of GDPR
1.5. Contact mail address
Turkish Statistical Institute (TurkStat) Devlet Mah.Necatibey Cad. No:114 06420 Çankaya/ANKARA
1.6. Contact email address
Confidential because of GDPR
1.7. Contact phone number
Confidential because of GDPR
1.8. Contact fax number
Confidential because of GDPR
2.1. Metadata last certified
28 May 2025
2.2. Metadata last posted
28 May 2025
2.3. Metadata last update
28 May 2025
3.1. Data description
Turnover is an important short term indicator used in the assessment of the economic situation in our country. Turnover Indices are calculated to follow the changes of this concept which is composed of sales of goods and services invoiced by the enterprise in the reference month over time, to monitor the development in quarterly and yearly basis, to provide data to academicians, students, and other groups of society, to have data consistent with the European Union regulations, to ensure the possibility of international comparisons and to form a resource for various researches for the turnover of the enterprises.
Services Turnover Index: It aims to show the development of turnover in services.
3.2. Classification system
NACE Rev. 2.
3.3. Coverage - sector
The indices are calculated according to the following NACE Rev. 2 economic activity classification;
section h – transportation and storage
section i – accommodation and food service activities
section j – information and communication
section l – real estate activities
section m – professional, scientific and technical activities
section n – administrative and support service activities
3.4. Statistical concepts and definitions
The variables used to calculate Turnover index:
Turnover comprises the total value of goods and services invoiced by enterprise in reference month and this corresponds to market sales of goods and services supplied to third parties. Turnover includes invoiced by unit vis-a-vis its customer other all taxes and duties. Turnover also includes all other charges (transport, packaging, etc.) passed on to the customer, even if these charges are listed separately in the invoice.
Turnover does not include price decline, discount and allowance, recycling package. The income which is classified in the company’s account as other business income, financial income and extraordinary income are excluded in turnover. Business subventions obtained from the government are also excluded.
3.5. Statistical unit
Kind of activity unit
3.6. Statistical population
The statistical population comprises the enterprises which submit VAT no.1 declaration to the Revenue Administration in Türkiye.
3.7. Reference area
Türkiye
3.8. Coverage - Time
Series of index starts from 2009.
3.9. Base period
2021=100
Indices and percentage changes.
Monthly
6.1. Institutional Mandate - legal acts and other agreements
Legal basis: Statistical Law of TurkStat no. 5429, of 10th November 2005 is the legal basis of all statistics.
regulation (eu) 2019/2152 of the european parliament and of the council of 27 november 2019 on european business statistics, repealing 10 legal acts in the field of business statistics
commission implementing regulation (eu) 2020/1197 of 30 july 2020 laying down technical specifications and arrangements pursuant to regulation (eu) 2019/2152 on european business statistics, repealing 10 legal acts in the field of business statistics
6.2. Institutional Mandate - data sharing
Unadjusted, calendar adjusted and seasonal and calendar adjusted indices are transmitted to Eurostat. If requested, indices are shared with all international and national instutions and researchers under data confidentiality rules.
7.1. Confidentiality - policy
All statistics collected and published by TurkStat are governed by the Turkish Statistical Law no. 5429, of 10 November 2005.
7.2. Confidentiality - data treatment
If the number of statistical units in any cell of the data table formed by aggregating the individual data is less than three, or if 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. Confidential data can be published only when combined with other data so as not to allow any direct or indirect identification. All measures to prevent any illicit access, use or revelation of the confidential data shall be taken by the institutions and organisations producing official statistics. 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. Confidential data can be accessed only by persons involved in the production of official statistics, to the extent that they are needed for performing their duties properly.
8.1. Release calendar
At the end of each year TurkStat publishes a release calendar providing the release dates for the coming year. This is also disseminated on TurkStat's internet website Data Release Calendar
8.2. Release calendar access
Publication dates and times of the press releases published by the Turkish Statistical Institute are available at Data Release Calendar
8.3. Release policy - user access
Simultaneous release to all interested parties: Data are released simultaneously to all interested parties by issuing the press release. The press release is subsequently disseminated TurkStat's Internet website.
Identification of internal government access to data before release: There is no special application for this item.
Transmission to Eurostat and further use of the statistics:Data is transmitted to Eurostat.
Monthly
10.1. Dissemination format - News release
Under the Statistical Law, any data product prepared under that law must be identified. Technical commentaries prepared by TurkStat accompany the news release.
Turnover Indices news release can be accessed from the link below.
Micro-data access is not available to the public or private users.
10.5. Dissemination format - other
Unadjusted, calendar adjusted and seasonal and calendar adjusted series are transmitted to Eurostat at the same day with the press release.
10.6. Documentation on methodology
Dissemination of documentation on methodology and sources used in preparing statistics: Dissemination of documentation on methodology and sources used in preparing statistics: Methodology and sources used in statistical compilation are disseminated on the Turkish Statistical Institute (TurkStat) website Methodology documentation
Description of standard tables produced: Data are given as indices at the 2-digit NACE Rev. 2 level in the press releases. Services Turnover Index (2021=100) is published.
10.7. Quality management - documentation
Not available.
11.1. Quality assurance
Not announced to public or not published but some quality checks are made for accuracy and quality assesment of indices. These are;
micro data and indices are examined by the group staff using sql codes in toad software
very high changes in companies' total, domestic and non-domestic turnover data are analyzed
impact and contribution analysis are done on enterprise basis by sectors
11.2. Quality management - assessment
Index is detected for below criterias;
relevance: getting opinions from users (public or private) about calculating indices, and taking technical support or advice from Eurostat staff
accuracy and reliability: data sources and results are regularly assessed and validated, and revisions to improve the statistical process are regularly analyzed
timeliness and punctuality: dissemination dates of press releases and indices are announced at the beginning of the year in the Data Release Calendar; any deviation from this calendar and the new publication date are shared with the public
comparability: all turnover indices are comparable with EU and other countries through methodological studies in close cooperation with Eurostat
coherence: Eurostat and other international disclosure standards are followed
12.1. Relevance - User Needs
The main users of statistical information are Eurostat, State institutions and agencies, international organisations, the media, research and business communities, students. The users' needs are satisfied without a breach of the confidentiality principle.
12.2. Relevance - User Satisfaction
Opinions from users (public or private) about calculating indices and technical support/advice from Eurostat staff always taken into consideration.
12.3. Completeness
Data are compliant with EU Regulations and national laws.
13.1. Accuracy - overall
Errors may be encountered due to incorrect coding of the activity at the source. Activity checks are made and enterprises that are found to have different activities from the activity specified in the source data are identified.
At the same time, enterprises whose turnover is incompatible with the series are questioned and their reasons are tried to be determined.
13.2. Sampling error
As all the enterprises that submit VAT no.1 declarations to the Revenue Administration are included in the index calculation, there is no sampling error.
13.3. Non-sampling error
Not available because of the usage of administrative sources.
14.1. Timeliness
42 days. Results are published in an average of 42 days from the reference month.
Timetable of data collection: VAT declarations are compiled monthly from the Revenue Administration on the 1-5th day of the month.
14.2. Punctuality
The press releases are published according to the announced release calendar.
15.1. Comparability - geographical
All turnover indices are comparable with EU and other countries. Methodological studies are done with close cooperation between Eurostat.
The same statistical definitions are applied in the entire Turkish national territory.
15.2. Comparability - over time
It is produced and disseminated average t+42 days. Index series start from 2009, there are no breaks in the series.
15.3. Coherence - cross domain
Comparisons are made with previous STS-values (previous month and year) and e-invoices.
15.4. Coherence - internal
There is internal consistency.
Not available.
17.1. Data revision - policy
In the series which are not seasonal and calendar adjusted;
1. Index values are revised for previous two months with the release of current month,
2. Index values are revised for last two years at the end of the reference period.
In the series which are seasonal and calendar adjusted;
1. Index values are revised each month for last three years,
2. According to system and methodology, if there is a change; the model structure, parameters and outlier structure are modified in the end of each year. Therefore series are revised.
Same revision policy is applied nationally and in transmissions to Eurostat.
17.2. Data revision - practice
Provision of information about revision and advance notice of major changes in methodology: The press releases indicates that the data are preliminary and are subject to revision. The preliminary results are final at the end of two years. Any major changes in methodology are announced at the time of the change and the data compiled using the revised methodology is released.
Benchmarking: Not available
18.1. Source data
Data source is administrative records
VAT no.1 declarations received monthly from the Revenue Administration are used.
Data is taken from the revenue administration via File Transfer Protocol (FTP). Afterwards, validations are done and the data is transferred to the database by the relevant IT unit .
18.2. Frequency of data collection
Monthly
18.3. Data collection
VAT no.1 declarations are compiled monthly from the Revenue Administration via File Transfer Protocol (FTP).
18.4. Data validation
Micro data and indices are examined by using sql codes in TOAD software.
18.5. Data compilation
Estimates for non-response: Not available.
Estimates for grossing-up to population levels: Not available
Type of index: A simple index is used which is calculated by dividing the relevant levels by the base year averages.
Method of weighting and chaining: Not available
Planned changes in production methods: Not available
18.6. Adjustment
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 crucial role in order to make reliable comparisons between consecutive periods
Method Used
The seasonal adjustment of Turnover Indices is carried out using TRAMO-SEATS methodology. The software that is used for the application of this method is JDemetra+ 2.2.2 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.
Process of the seasonal adjustment
Seasonal and calendar adjustment process of Turnover 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.
A substantial number of the subtitles of Turnover Indices contain seasonal and calendar effects.
Direct or indirect seasonal adjustment
Seasonally and calendar adjusted figures of Turnover Indices are produced by indirect approach. Firstly the three digit NACE Rev.2 classification individual subseries of Turnover Indices are seasonally adjusted and then aggregated to derive seasonally and calendar adjusted totals. The advantages of indirect approach are calculation of contributions to growth from components of main aggregates and retaining additivity.
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 is published 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
Residual seasonality is checked for 4-3-2 digit, section level and for each series
Consistency are done amongst the different levels of breakdown
Additional information about seasonal adjustment can be found at the annexes part.
Turnover is an important short term indicator used in the assessment of the economic situation in our country. Turnover Indices are calculated to follow the changes of this concept which is composed of sales of goods and services invoiced by the enterprise in the reference month over time, to monitor the development in quarterly and yearly basis, to provide data to academicians, students, and other groups of society, to have data consistent with the European Union regulations, to ensure the possibility of international comparisons and to form a resource for various researches for the turnover of the enterprises.
Services Turnover Index: It aims to show the development of turnover in services.
28 May 2025
The variables used to calculate Turnover index:
Turnover comprises the total value of goods and services invoiced by enterprise in reference month and this corresponds to market sales of goods and services supplied to third parties. Turnover includes invoiced by unit vis-a-vis its customer other all taxes and duties. Turnover also includes all other charges (transport, packaging, etc.) passed on to the customer, even if these charges are listed separately in the invoice.
Turnover does not include price decline, discount and allowance, recycling package. The income which is classified in the company’s account as other business income, financial income and extraordinary income are excluded in turnover. Business subventions obtained from the government are also excluded.
Kind of activity unit
The statistical population comprises the enterprises which submit VAT no.1 declaration to the Revenue Administration in Türkiye.
Türkiye
Monthly
Errors may be encountered due to incorrect coding of the activity at the source. Activity checks are made and enterprises that are found to have different activities from the activity specified in the source data are identified.
At the same time, enterprises whose turnover is incompatible with the series are questioned and their reasons are tried to be determined.
Indices and percentage changes.
Estimates for non-response: Not available.
Estimates for grossing-up to population levels: Not available
Type of index: A simple index is used which is calculated by dividing the relevant levels by the base year averages.
Method of weighting and chaining: Not available
Planned changes in production methods: Not available
Data source is administrative records
VAT no.1 declarations received monthly from the Revenue Administration are used.
Data is taken from the revenue administration via File Transfer Protocol (FTP). Afterwards, validations are done and the data is transferred to the database by the relevant IT unit .
Monthly
42 days. Results are published in an average of 42 days from the reference month.
Timetable of data collection: VAT declarations are compiled monthly from the Revenue Administration on the 1-5th day of the month.
All turnover indices are comparable with EU and other countries. Methodological studies are done with close cooperation between Eurostat.
The same statistical definitions are applied in the entire Turkish national territory.
It is produced and disseminated average t+42 days. Index series start from 2009, there are no breaks in the series.
