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.
Mining and Quarrying Sector (B), Manufacturing industry (C) and Electricity, Gas, Steam and Air Conditioning Supply (D) classified in NACE Rev.2 are covered.
35.12, 35.13, 35.14, 35.2, 35.3 and 09 sectors of NACE Rev.2 are not covered.
3.4. Statistical concepts and definitions
The Production Index is a volume index, and production is measured by the volume of output. The index measures the change in the volume of output generated by industrial enterprises in the mining and quarrying, manufacturing, and electricity, gas, steam and air conditioning supply sectors.
The index is estimated using the following data: deflated production value, deflated turnover for specific sectors (administrative data), production quantity, and hours worked.
For the following sectors: 05.10 - Mining of coal, 05.20 - Lignite mining, 06.10 - Crude oil extraction, 06.20 - Natural gas extraction, 12.00 - Production of tobacco products, and 35.11 - Electric energy production, the index is calculated using production quantity in the new series, as these are homogeneous. For sectors such as 30.11 - Construction of ships and floating structures, 30.12 - Manufacture of recreational and sporting structures, and 30.20 - Manufacture of railway locomotives and wagons, the sector indices are calculated using the total number of days worked, based on data from the Social Security Institution, since the production period exceeds a monthly cycle. For other sectors, deflated production value is used in the index calculation. The index measures the change in output generated by industrial enterprises in the mining, manufacturing, and electricity, gas, steam and air conditioning supply sectors.
The main sources of information for the index are the monthly production survey and the Revenue Administration database. The index covers the entire territory of Türkiye without geographical breakdown. Surveys are filled in by enterprises through a web-based platform. Administrative record data is used for enterprises where surveys are not conducted.
Data are recorded for the reference calendar month.
3.5. Statistical unit
Reporting unit : Enterprises and Kind of Activity Unit (KAU)
3.6. Statistical population
Enterprises, whose main activity is mining and quarrying (B) or manufacturing (C) or electricity, gas, steam and air conditioning supply (D) are covered.
The Industrial Production Index with 2021=100 reference years is calculated with the production values from approximately 7 thousand enterprises and the production value estimates obtained from the turnover of more than 400 thousand enterprises from the Revenue Administration.
3.7. Reference area
Whole Türkiye.
3.8. Coverage - Time
Monthly survey was being implemented since 2005 .
The publication calendar is set about 40. day (t + 40) after the end of the reference month.
3.9. Base period
Reference year : 2021
Indices and percentage changes.
Month.
6.1. Institutional Mandate - legal acts and other agreements
The legal basis is the Statistical Law no. 5429, of 10th November 2005. The obligation on units to provide data is done via compulsory surveys. Fines will be given in cases of non-response or deliberate reporting of wrong information according to the Statistical Law no. 5429. There is no planned changes in legal basis, obligation to respond and frame used.
The legal basis for the STS indicators are the Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics, repealing 10 legal acts in the field of business statistics (EBS-Regulation) and the Commission Implementing Regulation 2020/1197 laying down technical specifications and arrangements pursuant to Regulation (EU) 2019/2152 (General Implementing Act).
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
Data privacy and confidential data security regarding the statistics produced by Turkish Statistical Institute are guaranteed with the Turkish Statistical Law No. 5429 and the Regulation about Procedures and Principles of Data Privacy and Confidential Data Security of Official Statistics. Statistics are also prepared in accordance with the regulation published by the European Statistical Office (Eurostat) on March 11, 2009 with the number 223/2009 and the European Statistics Code of Practice, within the scope of harmonization with the European Union.The collection of data solely for statistical purposes and the confidentiality of the individual responses are guaranteed with the related legislation and regulations.
7.2. Confidentiality - data treatment
Only those involved in the production of official statistics can access confidential data to the extent they need it to perform their duties.
If the number of statistical units in any cell of the data table created by aggregation of individual data is less than three, or if the number of units is three or more, but one or two statistical units are dominant, the data in the relevant cell is considered confidential.
Confidential data collected, processed and stored for the production of official statistics cannot be given to any administrative, judicial or military organ, authority, authority or person, used for purposes other than statistics, and cannot be a means of proof. Officers and other officials who compile and evaluate this information must also comply with this prohibition. This obligation continues even after the officers leave their posts.
All kinds of precautions are taken by the authorities of the institutions and organizations that produce official statistics against the illegal access, disclosure or use of confidential data.
Data or information obtained from publicly available sources is not considered confidential.
In case the statistical unit gives written approval to the disclosure of confidential data belonging to it, data confidentiality is eliminated.
Confidential data can only be published by combining it with other information in a way that does not lead to direct or indirect identification.
The procedures and principles regarding data privacy and security are regulated by a regulation to be issued by taking the opinions of relevant institutions and organizations in line with national and international principles.
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 (TurkStat Website).
Any major changes in methodology are announced at the time of the change and the data compiled using the revised methodology is released.
The data are released simultaneously to all interested parties by issuing the news release Industrial Production Index.
The news release is prepared and kept secure under locked conditions until the specified time of release, at which time it is made available to the media and all interested parties.
Simultaneously, the news release is posted on the TurkStat website TurkStat Website
Identification of internal government access to data before release : no users have prior access to the data before its general release.
Transmission to Eurostat and further use of the statistics : At the time of national publication unadjusted data as well as calendar adjusted, seasonally and calendar adjusted data are transmitted to Eurostat via eDAMIS using SDMX (xml). The data have been sent in SDMX format to Eurostat since 2016.
Monthly (Within 40 days after the end of the reference month).
10.1. Dissemination format - News release
There are news releases on this indicator available in both Turkish and English versions.
The index is published at the total, section, and division level, as well as by MIGs and technology classification, for the reference month in the news release covering all industrial activities.
One standard basic table and three statistical tables are disseminated with the news release. Monthly changes are derived from seasonally and calendar-adjusted series. Annual changes are derived from calendar-adjusted series.
The details of the data disseminated in the news release are given below:
1 - Industrial Production Index and Change Rates (2021=100)
2 - Industrial Production Index Historical Indices (2021=100)
3 - Influence of Divisions on Upper Index Change (2021=100)
4 - Industrial Production Index and Change Rates (2021=100)
10.2. Dissemination format - Publications
The data are released simultaneously to all interested parties by issuing the news release Industrial Production Index. The news release is prepared and kept secure under locked conditions until the specified time of release, at which time it is made available to the media and all interested parties.
Simultaneously, the news release is posted on the Turkstat website TurkStat Website
10.3. Dissemination format - online database
Data are disseminated on the Industrial Production Index by using Chained LaspeyresIndex (2021=100). The index covers the mining and quarrying, manufacturing, and electricity, gas, steam and air conditioning supply.
The data are presented by main economic activities according to the NACE Rev. 2 classification, down into to group level.
The index is re-based and the weights are revised.
The data are seasonal and calendar adjusted at total index, section, division, group, Main Industrial Groupings (MIGs), technology classification economic activities level. Seasonal and calendar adjustment and calendar adjustment for Industrial Production Index are made by the direct method at the group level, and by the indirect method at other levels.
The data are released simultaneously to all interested parties on the Internet website of TurkStat issuing a Statistical release at the announced release calendar. A notification about the release is simultaneously mailed to the media and other subscribers of the news service via social media.
10.4. Dissemination format - microdata access
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 indices are transmitted to Eurostat.
10.6. Documentation on methodology
Methodology and sources used in statistical compilation are disseminated on the Turkish Statistical Institute (TurkStat) website TurkStat Website
The monthly news release provides a technical explanatory note about the data. In the web site full metadata can be accessed through the tab next to the news release. Also all statistical tables include metadata.
10.7. Quality management - documentation
Criterias for quality assessment in Turkish Statistical Institute are found at
Quality checks and validation of data are done throughout the whole compilation process.
Internal consistency checks are carried out at the analysis stage. As a part of the review process, changes in the Industrial Production Index are compared with Turnover Index and National Account Statistics.
11.2. Quality management - assessment
Industrial Production Index are detected for below criteria;
relevance; enterprises are checked, which indices are calculated from, main activities with SBS, BR and other surveys. Opinions from users (public or private) are sought on the calculation of indices, and technical support/advice is also sought from Eurostat staff.
accuracy and reliability; data source and results are regularly assessed and validated. Revisions to develop statistical process is analyzed regularly.
timeliness and punctuality; dissemination of news release and indices day and time announced to public at the beginning of the year. Can be accessed here. Data Release Calendar . Possible deviations from the publishing calendar, and a new date is notified to the public.
comparability; production index is comparable with EU and other countries. Methodological studies are done with close cooperation between Eurostat.
coherence; eurostat and other international standards are covered.
Indices are based on reliable data; Publication of results are always punctual; Multiple plausibility checks with different sources are done.
12.1. Relevance - User Needs
There are sections on the website of our institution for users who want to access both general and detailed information. After selecting the topic interested in from the "Subcategories" part of the "Statistics" section and clicking on the "Search" button, "News Release", "Statistical Tables", "Databases", "Reports" and "Metadata" contents can be reached.
Data at international and regional level can be accessed through the "Regional Statistics", "Provincial Indicators", "International Selected Indicators", and "Turkstat Library" applications in the "E-Services" section.
Data requests which cannot be replied are compiled regularly and data production process are addressed in the light of this information.
Short-term statistics are used by different national and international institutions and non-institutional users:
Institutions: Ministries, National Central Bank, political institutions (e.g. parliament), local authorities
International institutions: Eurostat, OECD, UN, IMF
Social actors: Trade unions
Researchers and Educational Institutions
Media
Enterprises/businesses
Internal users
Public
12.2. Relevance - User Satisfaction
Statistics produced by the Turkish Statistical Institute are presented to users through various channels, and a number of studies are carried out to increase service quality and meet user needs. The user satisfaction survey, which is one of these studies, is conducted through the corporate website in order to determine the profile, needs, and expectations of the users. The results of the survey are reported annually. However this survey is not applied especially to industrial statistics.
12.3. Completeness
STS requirements according to EU regulations are fulfilled.
13.1. Accuracy - overall
Surveys (Industrial Production survey) for the reference month are filled by enterprises between 11th-30th of following month. Forms filled out by the enterprises by using internet base programme. The survey response rate is approximately 99.9%. Non-responding units are followed up on telephone, e-mail or by interviewers. When a unit refuses to respond, the unit is reminded of its legal obligation to respond. In case of no response, the enterprise' turnover change rates are used (using VAT data).
Indices are revised regularly due to late response and occasionally due to the change in statistical methods, concepts, definitions, classifications and the base year.
In the unadjusted series;
1) While the current month indices are published, the month indices before the current month are revised.
2) Last year indices are revised in December news release.
For the Seasonal and Calendar Adjusted Series;
1) In calculating the index every month, the series are revised for the current year and the previous three years.
2) At the end of the year the model structure of the series, model parameters and the outliers observation structure will be changed if the method requires change.
First estimations are consistent with the revised indices calculated at the end of the year.
Data source and results are regularly assessed and validated. Revisions to develop statistical process is analyzed regularly.
13.2. Sampling error
Currently no calculations on sampling error are available for the Industrial Production Index on any level.
13.3. Non-sampling error
Response rate
Industrial production data were collected only by means of surveys till 2018. The 2010 = 100 based Industrial Production Index, which is published between 2013 and 2017, was calculated using survey data from approximately 10 thousand companies. As of March 2018, Revenue Administration microdata has been used to produce more comprehensive data sets, to reduce respondent burden and to make public resources more efficient. The Industrial Production Index with 2021=100 reference years is calculated with the production values from approximately 7 thousand enterprises and the production value estimates obtained from the sales of more than 400 thousand firms from the Revenue Administration in 2025.
Sampling error is not calculated for the survey.
There is no coverage problem in the frame.
The survey is compulsory. The response rate for industry is approximately 99%. A lot of checks are carried out at the micro and macro data level. For example the following processing errors may occur:
Human errors during the data editing process: these errors are often recognized with automated checks imputation errors: the imputed value is not within a plausible range plausibility errors: a lot of checks are carried out automatically e.g. check of completeness / sums / average rates / minimum-maximum values,…. The qualified checking of original respondent data, contacts to reporting units for corrections and the usage of sophisticated plausibility routines shall minimize the processing errors on micro-data-level.
Final checks with analyze-tables (aggregates/more complex relations). The macro data tabled are verified by computer programs but also by the staff whether these macro-data as publication figures look plausible. The persons responsible for the index calculation have their own computer programs to test the index-plausibility of the different data at group and division level and for all aggregates. If inconsistencies are detected the data must be verified at micro-level again by using the raw data of the questionnaire.
Actions to speed up or increase the rate of response
Non-responding units are followed up by telephone contacts, by e-mail or visits by field officers.
14.1. Timeliness
The indices are calculated monthly and disseminated in t+40 (average) days. All aggregation levels and sub-sectors are released at the same time. The results of the industrial production index are released on the 9-10th day of the second month following the reference month. The data are released simultaneously to all interested parties by issuing the news release “Industrial Production Index”.
The surveys of each reference month are filled by enterprises about 11 days after the reference month.
14.2. Punctuality
The news releases are published according to the announced release calendar.
15.1. Comparability - geographical
Industrial Production Index is comparable with EU. Methodological studies are done with close cooperation between Eurostat. The same statistical concepts are applied in the whole Türkiye. There is no geographical breakdown.
15.2. Comparability - over time
Data on the Industrial Production Index are comparable over time. When significant changes are made (for example, classification, base year, or methodology change), the historical time series is recalculated as far back as possible. According to NACE Rev.2, time series are available from 1986 onwards.
The 2021=100 Industrial Production Index is calculated using the chained Laspeyres method using annual averages. With the transition from fixed base year index calculation to chain Laspeyres chained index calculation, the most up-to-date weights have been used every year. Value added weights (t-1) obtained from National Accounts and Structural Business Statistics are used. The series based on 2021 = 100 and the series 2015 = 100 were linked using the annual average.
15.3. Coherence - cross domain
The Industrial Production Index can be compared with the following data;
Quarterly national account data, labour input indicators, tendency survey, turnover index, annual national accounts data, annual structural business statistics, annual industrial product statistics and annual retail trade statistics. The coherence between IPI and national accounts is high.
Cross-checks with;
absolute STS data in industry
compare over period: compare with previous STS-values (previous month and year)
SBS data (e.g. activity, turnover)
Other surveys e.g., foreign trade statistics and tendency Survey
15.4. Coherence - internal
The data is self-consistent. The compatibility of the data is checked with monthly, annual changes and time series.
Statistics on cost and burden are available for the Industrial Production Index. A one-time survey was implemented businesses for measurement of workload in 2015 and 2019. Statistics on cost and burden are not available for the year 2024.
17.1. Data revision - policy
Information about routine/major revisions to be implemented in the current period is crucial for statistics users in the sense of determining the validity of data. Because of changes in the reply of respondent unit and procedures such as seasonal and calendar effects adjustment, data might be revised routinely. This information is important for the validity of data in time. Summary information regarding the revision policies of statistics to be published within TurkStat in 2025 is given below link by topics.
Same revsion policy is applied nationally and in transmissions to Eurostat.
17.2. Data revision - practice
The news release indicates that the data are preliminary and are subject to revision. The preliminary results are finalized at the end of the reference year. Any major changes in methodology are announced at the time of the change, and the data compiled using the revised methodology is released.
Reasons for revision and methodology of revision for the Industrial Production Index are summarized below:
Revisions are made due to data that arrive too late for the index calculation and errors made by data providers.
Revisions are also made due to updates to the base year and changes in statistical methods, concepts, definitions, and classifications.
Revisions are also made as a result of seasonal and calendar adjustments.
Revision Policy
In the unadjusted series:
When indices for the current month are published, indices for the previous month are revised.
Indices for the previous year are revised in the December news release.
For the Seasonal and Calendar Adjusted Series:
In calculating the index each month, the series are revised for the current year and the previous three years.
At the end of the year, the model structure, model parameters, and outlier structure are revised if required by the methodology.
According to the system and methodology, if there is a change, the model structure, parameters, and outlier structure are modified at the end of each year. Therefore, the series are revised.
Historical data are stored in the database.
The indicator below refers to the average size of revisions, where a revision is defined as the difference between the first published and the latest published value. MR and MAR values were calculated using the information from the latest 36 available final releases.
Mean Revision: -0.03
Mean Absolute Revision: 0.64
Root Mean Squared Revision: 0.86
18.1. Source data
Data source: Data used for calculation of the index are consist of Monthly Industrial Production Survey data and turnover data calculated from Revenue Administration data base. The published data is temporary and data for the previous month is revised every month.
In addition data are obtained from Turkish Electricity Transmission Company (for electricity) and Tobacco and Alcohol Market Regulatory Authority.
Weights: Up to the level of the section according to NACE Rev. 2 classification (division level) weights obtained from the Structural Business Statistics are used. For the upper level indices National Accounts value added is used as a weight. For each level t-1 periods weights are used.
Variables: Production value, turnover, production quantity and number of days worked
In the index calculation the production quantity is used in sectors; 05- Mining of coal and lignite, 06- Extraction of crude petroleum and natural gas, 12- Manufacture of tobacco products and 35.11- Production of electricity. Total number of days worked obtained from the data of Social Security Institution is used in sectors; 30.11-Building of ships and floating structures, 3012- Building of pleasure and sporting boats and 30.20- Manufacture of railway locomotives and rolling stock. In the index calculation deflated production value and turnover is used for other sectors.
Deflator: Domestic and non-domestic producer prices
Type of index: Chained Laspeyres Index method (weighted) is used.
Classification: Nace Rev.2
18.2. Frequency of data collection
All data is collected on a monthly basis.
18.3. Data collection
The main data source for the industrial production index is the survey. The turnovers obtained from VAT declarations are also used together with the survey. While data is obtained from the enterprises (approximately 7 thousand enterprises) with a coverage rate of approximately 70% in the sector (quads) by survey, the turnover information obtained from the declarations of the other enterprises is used.
The survey form is entered by the enterprises through the web based Harzemli application. The data compiled with the survey until 2014 are compiled by the workplaces (by making data entry) with the Harzemli Platform as of this date.
This program enables the compilation of data previously collected in various ways or via e-mail over the internet. Harzemli Platform; We can define it as a platform that enables the use of standards for TurkStat and statistical data producers and automatically turns a question paper into a data entry application.
It offers software for all processes such as needs analysis, data entry application, analysis reports, error tracking, field management, data distribution.
Harzemli application has been prepared in such a way that it does not allow data entry of an erroneous or incomplete question paper by checking for consistency at various points.
Like this
• Incomplete information is not compiled,
• Minimizing erroneous data entry,
• Increasing data quality,
• It is aimed to reduce long data processing processes.
As of March 2018, micro data of the Revenue Administration is used in order to produce more comprehensive data sets, reduce the burden of respondents and use public resources more efficiently.
18.4. Data validation
The data entry control of the survey is performed by the Regional Offices via a web based computer software. The software for the data entry is designed to check the consistency at several points and not to allow entering wrong or missing data.
Appropriate validation procedures are applied during the whole production process of statistics, and they are in line with rules provided by Eurostat, i.e. starting from selection of respondents to compiling indices and transmission to Eurostat. Data validation system incorporates many tools for data control, estimation and imputation, e.g. programme procedures applied for error checking and detailed reports on data completeness helpful in analysis of non-response. Validation procedures are applied on the level of individual respondents and on aggregated level as well as before data transmission to Eurostat. Data validation on the level of individual respondents is based on: special programme procedures used for errors checking when data are inserted to the system these procedures help to avoid errors at the stage of data collection what is essential for final data results. information given by an enterprise on the reasons of substantial difference in the level of data reported in the current period as compared to the equivalent data for the previous period.
In the case of any doubts about data correctness there is a direct contact with an enterprise in order to explain outliers. Both the values and dynamics are compared with previous month and corresponding month of the previous year. Validation procedures are also performed before data transmission to Eurostat. The structured data files in SDMX format are created and data assigned to the codes are checked in detail. In case of significant data revisions, for example when the base year changes or seasonal adjusted data are revised, the whole time series are submitted to validation procedure.
18.5. Data compilation
Estimates for non-response
There is rigorous follow-up of nonresponding units. If enterprises refuse to respond, the unit is reminded of its legal obligation to respond. But if the problem persists, imputation process is applied for the unit. In non response situation, the change rate of turnover of the sectors are used for imputation.
Estimates for grossing-up to population levels
Sample results are not grossed-up.
Type of index
Chained Laspeyres Index method (weighted) is used.
Method of weighting and chaining
Up to the level of the section according to NACE Rev. 2 classification (division level) weights obtained from the Annual Industrial and Service Statistics are used. For the upper level indices National Accounts value added is used as a weight. For each level t-1 periods weights are used.
Planned changes in production methods
TurkStat do not plan any changes for the production method.
18.6. Adjustment
Seasonal 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 Industrial Production Indices is carried out using TRAMO-SEATS methodology. The software that is used for the application of this method is 2.2.2 version of 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 Industrial Production 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.
Direct or Indirect Approach
NACE Rev.2 class series are seasonally and calendar adjusted by direct approach and then aggregated to derive seasonally and calendar adjusted group, division figures, MIGs and IPI. The advantages of indirect approach are calculation of contributions to growth from components of main aggregates and retaining additivity.
Revision Policy
The Revision Information Form regarding the revisions to be carried out in the current year for the statistics produced in the scope of this news release can be accessed from the link below.
1) While the current month indices are published, the month indices before the current month are revised.
2) Last year indices are revised in December news release.
For the Seasonal and Calendar Adjusted Series;
1) In calculating the index every month, the series are revised for the current year and the previous three years.
2) At the end of the year the model structure of the series, model parameters and the outliers observation structure will be changed if the method requires change.
Publication
Adjusted data has been published in 3 different ways.
1- “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.
2- “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.
3 - 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.
The Production Index is a volume index, and production is measured by the volume of output. The index measures the change in the volume of output generated by industrial enterprises in the mining and quarrying, manufacturing, and electricity, gas, steam and air conditioning supply sectors.
The index is estimated using the following data: deflated production value, deflated turnover for specific sectors (administrative data), production quantity, and hours worked.
For the following sectors: 05.10 - Mining of coal, 05.20 - Lignite mining, 06.10 - Crude oil extraction, 06.20 - Natural gas extraction, 12.00 - Production of tobacco products, and 35.11 - Electric energy production, the index is calculated using production quantity in the new series, as these are homogeneous. For sectors such as 30.11 - Construction of ships and floating structures, 30.12 - Manufacture of recreational and sporting structures, and 30.20 - Manufacture of railway locomotives and wagons, the sector indices are calculated using the total number of days worked, based on data from the Social Security Institution, since the production period exceeds a monthly cycle. For other sectors, deflated production value is used in the index calculation. The index measures the change in output generated by industrial enterprises in the mining, manufacturing, and electricity, gas, steam and air conditioning supply sectors.
The main sources of information for the index are the monthly production survey and the Revenue Administration database. The index covers the entire territory of Türkiye without geographical breakdown. Surveys are filled in by enterprises through a web-based platform. Administrative record data is used for enterprises where surveys are not conducted.
Data are recorded for the reference calendar month.
Reporting unit : Enterprises and Kind of Activity Unit (KAU)
Enterprises, whose main activity is mining and quarrying (B) or manufacturing (C) or electricity, gas, steam and air conditioning supply (D) are covered.
The Industrial Production Index with 2021=100 reference years is calculated with the production values from approximately 7 thousand enterprises and the production value estimates obtained from the turnover of more than 400 thousand enterprises from the Revenue Administration.
Whole Türkiye.
Month.
Surveys (Industrial Production survey) for the reference month are filled by enterprises between 11th-30th of following month. Forms filled out by the enterprises by using internet base programme. The survey response rate is approximately 99.9%. Non-responding units are followed up on telephone, e-mail or by interviewers. When a unit refuses to respond, the unit is reminded of its legal obligation to respond. In case of no response, the enterprise' turnover change rates are used (using VAT data).
Indices are revised regularly due to late response and occasionally due to the change in statistical methods, concepts, definitions, classifications and the base year.
In the unadjusted series;
1) While the current month indices are published, the month indices before the current month are revised.
2) Last year indices are revised in December news release.
For the Seasonal and Calendar Adjusted Series;
1) In calculating the index every month, the series are revised for the current year and the previous three years.
2) At the end of the year the model structure of the series, model parameters and the outliers observation structure will be changed if the method requires change.
First estimations are consistent with the revised indices calculated at the end of the year.
Data source and results are regularly assessed and validated. Revisions to develop statistical process is analyzed regularly.
Indices and percentage changes.
Estimates for non-response
There is rigorous follow-up of nonresponding units. If enterprises refuse to respond, the unit is reminded of its legal obligation to respond. But if the problem persists, imputation process is applied for the unit. In non response situation, the change rate of turnover of the sectors are used for imputation.
Estimates for grossing-up to population levels
Sample results are not grossed-up.
Type of index
Chained Laspeyres Index method (weighted) is used.
Method of weighting and chaining
Up to the level of the section according to NACE Rev. 2 classification (division level) weights obtained from the Annual Industrial and Service Statistics are used. For the upper level indices National Accounts value added is used as a weight. For each level t-1 periods weights are used.
Planned changes in production methods
TurkStat do not plan any changes for the production method.
Data source: Data used for calculation of the index are consist of Monthly Industrial Production Survey data and turnover data calculated from Revenue Administration data base. The published data is temporary and data for the previous month is revised every month.
In addition data are obtained from Turkish Electricity Transmission Company (for electricity) and Tobacco and Alcohol Market Regulatory Authority.
Weights: Up to the level of the section according to NACE Rev. 2 classification (division level) weights obtained from the Structural Business Statistics are used. For the upper level indices National Accounts value added is used as a weight. For each level t-1 periods weights are used.
Variables: Production value, turnover, production quantity and number of days worked
In the index calculation the production quantity is used in sectors; 05- Mining of coal and lignite, 06- Extraction of crude petroleum and natural gas, 12- Manufacture of tobacco products and 35.11- Production of electricity. Total number of days worked obtained from the data of Social Security Institution is used in sectors; 30.11-Building of ships and floating structures, 3012- Building of pleasure and sporting boats and 30.20- Manufacture of railway locomotives and rolling stock. In the index calculation deflated production value and turnover is used for other sectors.
Deflator: Domestic and non-domestic producer prices
Type of index: Chained Laspeyres Index method (weighted) is used.
Classification: Nace Rev.2
Monthly (Within 40 days after the end of the reference month).
The indices are calculated monthly and disseminated in t+40 (average) days. All aggregation levels and sub-sectors are released at the same time. The results of the industrial production index are released on the 9-10th day of the second month following the reference month. The data are released simultaneously to all interested parties by issuing the news release “Industrial Production Index”.
The surveys of each reference month are filled by enterprises about 11 days after the reference month.
Industrial Production Index is comparable with EU. Methodological studies are done with close cooperation between Eurostat. The same statistical concepts are applied in the whole Türkiye. There is no geographical breakdown.
Data on the Industrial Production Index are comparable over time. When significant changes are made (for example, classification, base year, or methodology change), the historical time series is recalculated as far back as possible. According to NACE Rev.2, time series are available from 1986 onwards.
The 2021=100 Industrial Production Index is calculated using the chained Laspeyres method using annual averages. With the transition from fixed base year index calculation to chain Laspeyres chained index calculation, the most up-to-date weights have been used every year. Value added weights (t-1) obtained from National Accounts and Structural Business Statistics are used. The series based on 2021 = 100 and the series 2015 = 100 were linked using the annual average.
