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 Business Statistics Department (Industrial Statistics 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 06100 Çankaya/ Ankara/ Türkiye
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
13 January 2025
2.2. Metadata last posted
13 January 2025
2.3. Metadata last update
13 January 2025
3.1. Data description
Index of Production in Construction
3.2. Classification system
NACE Rev.2
3.3. Coverage - sector
F (Construction), 41 (Construciton of buildings), 42 (Civil engineering), 43 (Specialised construction activities) in NACE Rev.2 are covered.
3.4. Statistical concepts and definitions
The index of production in construction measures the volumetric change in outputs produced in the construction of buildings, civil engineering and specialised construction activities sectors through the inputs of materials and labor used in these sectors.
Material input; it is the monetary value paid by enterprises operating in the construction sector for the materials they purchase during the construction process.
Labor input; it is the wages paid to employees by enterprises operating in the construction sector.
3.5. Statistical unit
Enterprise
3.6. Statistical population
In Turkey in reference year, the activities of enterprises in the construction of buildings (41), civil engineering (42) and specialised construction activities (43) sectors according to NACE Rev.2 are included.
3.7. Reference area
Whole country (Türkiye)
3.8. Coverage - Time
The index of production in construction has been available since 2017.
3.9. Base period
2021=100
Indices and percentage change
Monthly
6.1. Institutional Mandate - legal acts and other agreements
The compilation and dissemination of the data are governed by the Turkish Statistical Law No. 5429 of November 10, 2005. The purpose of this law is to determine basic principles and standards concerning the production and organisation of official statistics; and to regulate the formation, duties, and authorities of the Turkish Statistical Institute (TurkStat) which is to compile and assess data and information, produce, publish, and disseminate statistics on the areas that country needs, and to ensure coordination among institutions and organizations that are involved in the statistics process prescribed in the Official Statistics Programme (Article 1).
The Official Statistics Programme establishes the framework for official statistics that shall be produced on subjects required at national and international level. Censuses and surveys are carried out within the framework of this Programme (Article 3).
6.2. Institutional Mandate - data sharing
Unadjested, calendar adjusted and seasonal and calendar adjusted indices are submitted to Eurostat every month. Indices are shared with all international and national institutions and researchers upon request, within the framework of data privacy 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.
8.1. Release calendar
The data release calendar for statistical outputs is prepared on an annual basis and it is publicly announced on the National Data Release Calendar section of the website.
8.2. Release calendar access
Publication dates and times of the press releases published by the Turkish Statistical Institute are available at National Data Release Calendar.
The principles, standards and procedures regarding the publication and dissemination of statistics produced by Turkish Statistical Institute are determined by the Publication and Dissemination Board. In order to ensure that statistics are delivered to users in accordance with the principles of confidentiality and equal access, and in an accurate, reliable, consistent, timely, and transparent way, the publishing dates of the press releases are determined within the framework of the Directive on the Procedures and Principles Regarding the Working Calendars of the Presidency of the Turkish Statistical Institute and announced to the public via the institutional website at the beginning of each year.
Monthly
10.1. Dissemination format - News release
Index of Production in Construction
A standard basic table and a statistical table are published in the press release. Monthly changes are derived from seasonal and calendar adjusted series. Annual changes are derived from calendar adjusted series.
The details of data which are disseminated in press release are given below
Index of Production in Construction and change rates (2021=100);
Index of Production in Construction and change rates (2021=100) (statistical table).
European Statistics Code of Practice (CoP) are the quality principles and standards established by the European Union. CoP; It consists of 3 main sections: institutional environment, statistical processes and statistical outputs. There are 16 quality principles and 84 quality indicators under these principles. TurkStat carries out its activities in accordance with the CoP's quality principles and indicators. The CoP is available on the Eurostat's website.
Institutional quality reports are prepared for annual studies. The relevant quality report can be accessed under the Metadata tab on the Statistics Data Portal.
Quality-related documents were created within the scope of the ISO 9001:2015 Quality Management standard. Procedures, guides, instructions, plans, lists, and forms are included in the quality management system along with the standard coding system. There is a "Document Control Procedure" for the creation and updating of the documents. In addition, all studies are detailed on the basis of the articles of the standard in the "Quality Handbook", prepared within the scope of the ISO 9001:2015 Quality Management standard.
11.1. Quality assurance
TurkStat Quality Policy
TurkStat is committed to implementing a quality policy based on the European Statistics Code of Practice (ES-CoP), the European Statistical System Quality Assurance Framework (ESS-QAF), and other internationally recognized best practices determined by the European Statistical Office (Eurostat). In this context, TurkStat strictly adheres to and implements quality standards in statistical production processes by adopting the principle of continuous improvement and excellence in accordance with the ISO 9001:2015 Quality Management System Standard.
TurkStat Quality Policy is avaliable on the TurkStat website.
The Quality Assurance Framework of the European Statistical System (ESS QAF) is a supporting document that aims to assist in the implementation of the European Statistics Code of Practice (CoP). It identifies possible activities, methods and tools that can provide guidance and evidence for the implementation of the CoP's indicators. TurkStat has determined its own quality assurance framework according to the QAF and shares it with all users on the TurkStat website. In line with the principles of the CoP, TurkStat quality assurance framework includes the studies, tools and legal regulations.
TurkStat is certified by the “ISO 9001:2015 Quality Management System” standard. TurkStat implements a holistic quality management system by fulfilling all the necessary requirements of the standard.
11.2. Quality management - assessment
Quality Monitoring and Assessment Tool (QMAT)
TurkStat aims to increase the quality of statistics by evaluating the compliance of official statistics produced with quality principles and standards based on European Statistics Practice Principles (Code of Practice-CoP). As a result of the quality assessment carried out with QMAT, areas open to improvement are determined and improvement action plans are created. The actions scheduled in the improvement action plan are regularly monitored to ensure continuous improvement in the quality of official statistics.
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, "Press 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.
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.
The index of production in construction is fully compliant with the STS Regulation. According to the STS regulation, the data completeness rate is 100%.
13.1. Accuracy - overall
The data used to calculate this indicator is obtained from administrative records. Impact analysis is performed for the data used each month, and if there is a deviation due to incorrect values in material and labor inputs, it is compared with different indicators such as turnover data and necessary corrections are made.
13.2. Sampling error
Not applicable.
13.3. Non-sampling error
Not applicable.
14.1. Timeliness
45 days. Results are published in an average of 45 days from the reference month.
14.2. Punctuality
The news releases are published according to the announced release calendar.
15.1. Comparability - geographical
The Index of Production in Construction is produced and published in accordance with the European Union Short-Term Business Statistics Regulation. This index is not expected to be generated using a single method applicable to all countries; rather, each country is expected to produce it based on its available data and the most appropriate methodology. In Turkey, this indicator is calculated using administrative records that include the majority of inputs used in construction production. The index is published monthly and in a timely manner. The publication includes details such as unadjusted indices, calendar-adjusted indices, seasonally and calendar-adjusted indices, as well as monthly and annual changes.
The Index of production in construction is comparable with the index of production in construction of all countries that publish their indicators in accordance with the European Union Short-Term Business Statistics Regulation.
15.2. Comparability - over time
The data related to the Index of Production in Construction is comparable over time. The series for this indicator have been calculated starting from 2017, with a base year of 2021=100. The calculation uses the fixed-based laspeyres index method. When significant changes occur (such as classification, base year, or methodological changes), the historical series will be recalculated retrospectively.
15.3. Coherence - cross domain
The Index of Production in Construction is comparable with national accounts and short-term turnover data.
15.4. Coherence - internal
The data is self-consistent. The compatibility of the data is checked with monthly, annual changes and time series.
No survey is conducted for the index of production in construction.
17.1. Data revision - policy
Revision Policy
For reliable, comparable, compatible and consistent production of the current statistics by ensuring data integration; strategies have been specified in "Directive on Methods and Principles Regarding Revisions on Statistical Data Produced by Turkish Statistical Institute" . In this context, the general framework with regard to which statistics are to be revised, why, how long and how deep is available via the website.
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. In this context, TurkStat has adopted the principle of releasing the routine and/or major revision status of all statistical topics to be published in the beginning of each calendar year via the website.
Same revision policy is applied nationally and in transmissions to Eurostat.
17.2. Data revision - practice
In the series that are not adjusted for seasonal and calendar effects;
While the current month indices are published, the month indices before the current month are revised.
Current year and last two years indices are revised in December press release.
In the series adjusted for seasonal and calendar effects;
In calculating the index every month, the series are revised for the current year and the previous three years.
At the end of the year, according to the method and system; If there is a change, the model structure, model parameters and outlier observation structure of the series will be changed. Therefore, the series are revised.
18.1. Source data
Data Sources:
The data used to calculate the index of production in construction is sourced from administrative records.
Form BS – Form BA records: This data are provided by the Revenue Administration. Material input is calculated using invoices issued to enterprises whose main activity is construction.
E-Invoice Data: This data are provided by the Revenue Administration. Material input is calculated using e-invoices issued to enterprises whose main activity is construction.
(SSI) Monthly Premium and Service Return: This data is provided by the Social Security Institution. The payments made to employees by enterprises whose main activity is construction are used as labor input.
The combination of these two data sources provides the total input data.
18.2. Frequency of data collection
Monthly
18.3. Data collection
The Index of Production in Construction is calculated based on administrative records. The calculation of this index utilizes invoice data from approximately 260,000 enterprises whose main activity belongs to sections 41 (Building construction), 42 (Civil engineering) and 43 (Specialized construction activities) of the NACE Rev.2 classification, along with data on employee payment recorded in the monthly premium and service documents of these enterprises.
The administrative records are received by our institution between the 25th and 30th days of the month following the reference month.
18.4. Data validation
The turnover information of enterprises is used to verify the e-invoice data. If the total amount of invoices issued by a enterprise exceeds its total turnover, incorrectly issued invoices are corrected using the turnover data.
When payments made to employees are used as input, the analysis is completed by the labor input indicators group using the impact analysis method.
18.5. Data compilation
The index of production in construction is calculated based on the material inputs and labor payments of enterprises operating in the sectors of building construction (41), civil engineering (42), and specialized construction activities (43) according to the NACE Rev.2 classification.
Material inputs are calculated using the invoices issued by enterprises that produce, trade and provide services related to these materials to construction firms. Until July 2021, Form Ba (purchase invoices) and Form Bs (sales invoices) records were used to determine these inputs, but as of this date, e-invoice records have been used. The obligation for e-invoicing has been gradually increasing each year since 2021. However, there are enterprises in the construction sector that do not have e-invoice data. In such cases, material input values at the enterprise level are estimated using labor payments for each month. For these estimates, the data of enterprises with both material and labor payment records at the class level (four-digit) are collected, and the ratio of material inputs to labor inputs is determined.
This ratio is then applied to the labor payments of enterprises without material input data, thereby estimating the material inputs for these enterprises. The material inputs for each month are calculated by taking the average of the current month and the previous two months.
The index of production in construction is calculated using the volume value formed by separately deflating material and labor inputs and summing them. The material input is deflated using the material component of the construction cost index for the relevant sector, while the labor input is deflated using the labor component of the construction cost index for the relevant sector.
As a result, the volume values of total inputs are obtained both at the section (total) level and division (two-digit) level. These volume values are aligned with the volume value of the annual accounts (benchmarked). The bench ratio is determined by using the input volume value calculated at the letter level and the volume value of the Gross Domestic Product based on the production method. For past years' data, the bench ratio of the same year is used, while for 2023 and beyond, the most recent years' data will be used.
The index of production in construction is calculated using the fixed-base Laspeyres index method (2021=100) with the benchmarked total input volume values. Total index are calculated by weighting the division-level indices with annual value-added data.
The index of production in construction, published monthly (t+45), includes unadjested indices, calendar-adjusted indices, seasonally and calendar-adjusted indices, as well as monthly and annual changes.
18.6. Adjustment
Index of production in construction seasonal adjustment
Seasonal and calendar effects, as they are temporary, prevent the observation of the general trend of the data. Therefore, determining the seasonal structure in short-term indicators; plays an extremely important role in making reliable comparisons between consecutive periods.
Method Used
The seasonal and calendar effects of the index of production in construction are adjusted using the TRAMO-SEATS (Gomez and Maravall, 1996) method. In the implementation of this method, JDemetra+ 2.2.2 software, which was developed by the Belgian Central Bank in cooperation with the German Central Bank and the European Union Statistical Office, in line with the European Statistical System guidelines is used.
Seasonal Correction Process
The seasonal adjustment process of the index of production in construction starts at the end of each year with the determination of the model specifications of the next year. This model structure, which is determined for seasonal and/or calendar adjustment, is kept constant throughout the year. At the end of the year, similar to the previous year, the econometric model specifications of the next year are determined. This process is repeated cyclically every year.
Most of the sub-items that make up the Index of Production in Construction (IPC) have seasonal and calendar effects.
Direct or Indirect Approach
Seasonally and calendar adjusted NACE Rev.2 divison level data are directly adjusted to obtain section level data, indirectly. Indirect approach; It has the advantages of easily calculating the contribution of the sub-components to the total growth and providing the additive relationship.
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 has been 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.
The index of production in construction measures the volumetric change in outputs produced in the construction of buildings, civil engineering and specialised construction activities sectors through the inputs of materials and labor used in these sectors.
Material input; it is the monetary value paid by enterprises operating in the construction sector for the materials they purchase during the construction process.
Labor input; it is the wages paid to employees by enterprises operating in the construction sector.
Enterprise
In Turkey in reference year, the activities of enterprises in the construction of buildings (41), civil engineering (42) and specialised construction activities (43) sectors according to NACE Rev.2 are included.
Whole country (Türkiye)
Monthly
The data used to calculate this indicator is obtained from administrative records. Impact analysis is performed for the data used each month, and if there is a deviation due to incorrect values in material and labor inputs, it is compared with different indicators such as turnover data and necessary corrections are made.
Indices and percentage change
The index of production in construction is calculated based on the material inputs and labor payments of enterprises operating in the sectors of building construction (41), civil engineering (42), and specialized construction activities (43) according to the NACE Rev.2 classification.
Material inputs are calculated using the invoices issued by enterprises that produce, trade and provide services related to these materials to construction firms. Until July 2021, Form Ba (purchase invoices) and Form Bs (sales invoices) records were used to determine these inputs, but as of this date, e-invoice records have been used. The obligation for e-invoicing has been gradually increasing each year since 2021. However, there are enterprises in the construction sector that do not have e-invoice data. In such cases, material input values at the enterprise level are estimated using labor payments for each month. For these estimates, the data of enterprises with both material and labor payment records at the class level (four-digit) are collected, and the ratio of material inputs to labor inputs is determined.
This ratio is then applied to the labor payments of enterprises without material input data, thereby estimating the material inputs for these enterprises. The material inputs for each month are calculated by taking the average of the current month and the previous two months.
The index of production in construction is calculated using the volume value formed by separately deflating material and labor inputs and summing them. The material input is deflated using the material component of the construction cost index for the relevant sector, while the labor input is deflated using the labor component of the construction cost index for the relevant sector.
As a result, the volume values of total inputs are obtained both at the section (total) level and division (two-digit) level. These volume values are aligned with the volume value of the annual accounts (benchmarked). The bench ratio is determined by using the input volume value calculated at the letter level and the volume value of the Gross Domestic Product based on the production method. For past years' data, the bench ratio of the same year is used, while for 2023 and beyond, the most recent years' data will be used.
The index of production in construction is calculated using the fixed-base Laspeyres index method (2021=100) with the benchmarked total input volume values. Total index are calculated by weighting the division-level indices with annual value-added data.
The index of production in construction, published monthly (t+45), includes unadjested indices, calendar-adjusted indices, seasonally and calendar-adjusted indices, as well as monthly and annual changes.
Data Sources:
The data used to calculate the index of production in construction is sourced from administrative records.
Form BS – Form BA records: This data are provided by the Revenue Administration. Material input is calculated using invoices issued to enterprises whose main activity is construction.
E-Invoice Data: This data are provided by the Revenue Administration. Material input is calculated using e-invoices issued to enterprises whose main activity is construction.
(SSI) Monthly Premium and Service Return: This data is provided by the Social Security Institution. The payments made to employees by enterprises whose main activity is construction are used as labor input.
The combination of these two data sources provides the total input data.
Monthly
45 days. Results are published in an average of 45 days from the reference month.
The Index of Production in Construction is produced and published in accordance with the European Union Short-Term Business Statistics Regulation. This index is not expected to be generated using a single method applicable to all countries; rather, each country is expected to produce it based on its available data and the most appropriate methodology. In Turkey, this indicator is calculated using administrative records that include the majority of inputs used in construction production. The index is published monthly and in a timely manner. The publication includes details such as unadjusted indices, calendar-adjusted indices, seasonally and calendar-adjusted indices, as well as monthly and annual changes.
The Index of production in construction is comparable with the index of production in construction of all countries that publish their indicators in accordance with the European Union Short-Term Business Statistics Regulation.
The data related to the Index of Production in Construction is comparable over time. The series for this indicator have been calculated starting from 2017, with a base year of 2021=100. The calculation uses the fixed-based laspeyres index method. When significant changes occur (such as classification, base year, or methodological changes), the historical series will be recalculated retrospectively.
