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.
Data Governance and Statistics Department, Surveys and Indices Division
1.3. Contact name
Restricted from publication
1.4. Contact person function
Restricted from publication
1.5. Contact mail address
Saray Mah. Küçüksu Cad. No: 64/B Ümraniye İstanbul/TÜRKİYE
1.6. Contact email address
Restricted from publication
1.7. Contact phone number
Restricted from publication
1.8. Contact fax number
Restricted from publication
2.1. Metadata last update
26 January 2024
2.2. Metadata last certified
26 January 2024
2.3. Metadata last posted
26 January 2024
3.1. Data description
Dwelling prices indicated in valuation reports prepared at the time of approval of individual housing loans are used as a proxy for price. Valuation reports which form a basis for housing loans are prepared by real estate appraisal companies. The actual sale of the property and utilization of the loan is not required and all dwellings appraised are included in the scope.
Following indicators are produced on a monthly basis:
Residential Property Price Index (RPPI)
Residential Property Price Index for New Dwellings (NRPPI)
Residential Property Price Index for Existing Dwellings (ERPPI)
Unit Price
3.2. Classification system
Nomenclature of Territorial Units for Statistics (NUTS): Regional unit classification designed for the whole country in compliance with the European Union Regional Statistics System to develop a comparable statistical database.
Level: Regional units formed according to NUTS.
NUTS Level 3: 81 regional levels corresponding to cities.
NUTS-Level 2: 26 regional levels formed by combining NUTS-Level 3 units.
Nomenclature of Territorial Units for Statistics (NUTS) is used for aggregating the data. The data are aggregated at the 3rd and 2nd levels of NUTS respectively for RPPI and ERPPI and the overall indices for Türkiye are constructed using the data aggregated at the 2nd level. NRPPI is constructed using the data aggregated at the 3rd level and the index for Türkiye is constructed using the data aggregated at the 3rd level.
3.3. Coverage - sector
Household sector.
3.4. Statistical concepts and definitions
Residential Property Price Index (RPPI): Residential property price index constructed using hedonic regression method in which prices are adjusted for quality changes related to observed housing characteristics. Residential Property Price Index for New Dwellings (NRPPI): Price index constructed using hedonic regression method for dwellings built in the current and the previous years covering the whole country. Residential Property Price Index for Existing Dwellings (ERPPI): Price index constructed using hedonic regression method for the dwellings built before the current and the previous years covering the whole country.
Unit Price: Price calculated by dividing the value of a property by its gross area of use.
3.5. Statistical unit
Appraisal values of dwellings.
3.6. Statistical population
The target population is the set of valuations of all types of dwellings prepared by real estate companies.
3.7. Reference area
The RPPI and ERPPI, which are constructed to represent the whole country, cover appraised dwellings in 74 cities. While constructing the NRPPI, which also represents the whole country, data pertaining to the valuations of new dwellings in 51 cities where there are sufficient number of observations are used.
The national RPPI, ERPPI and NRPPI are weighted averages of the regional indices. RPPI is published for the whole country and on the basis of NUTS Level 2, whereas NRPPI and ERPPI are published for the whole country and for the three major cities.
3.8. Coverage - Time
Data are available from January 2010.
3.9. Base period
2017=100
Following units are used:
Index figures with reference to the year 2017 Annual and monthly percentage changes Unit prices in national currency (Turkish Liras)
Relevant month.
6.1. Institutional Mandate - legal acts and other agreements
Article 43, CBRT Law No. 1211, as amended on April 25, 2001 by the Law No. 4651 Turkish Statistics Law No. 5429 - Official Statistics Program
6.2. Institutional Mandate - data sharing
Not applicable.
7.1. Confidentiality - policy
Article 43, CBRT Law No. 1211, as amended on April 25, 2001 by the Law No. 4651 Turkish Statistics Law No. 5429 - Official Statistics Program
7.2. Confidentiality - data treatment
Not applicable.
8.1. Release calendar
The release calendar is announced to the public in advance and published on the first business day of each year on the website of the CBRT.
The institutions and organizations which are the subscribers of the data delivery system are informed about the publication of the results just after they are made available on the website of the CBRT.
Methodological paper can be found at CBRT webpage. (A Hedonic House Price Index for Turkey, Timur Hülagü, Erdi Kızılkaya, Ali Gencay Özbekler, Pınar Tunar, 2016)
10.7. Quality management - documentation
Not available.
11.1. Quality assurance
All data are checked for completeness and consistency with statistical concepts and definitions. Automatic quality controls have been implemented within the RPPI production process in order to detect and correct errors in the data files that are received. Outliers, such as dwellings with very high or low unit prices and mass valuations are excluded from the index.
11.2. Quality management - assessment
Not available.
12.1. Relevance - User Needs
Policy makers; Commercial banks; Real estate appraisal companies; Economic analysts.
12.2. Relevance - User Satisfaction
The “Statistics Users Survey” is conducted in order to monitor users' needs.
12.3. Completeness
Since transaction data have quality issues, indices are produced based on appraisal data. Quality of transaction data could be improved and indices could be produced based on transactions.
13.1. Accuracy - overall
Not available.
13.2. Sampling error
Not available.
13.3. Non-sampling error
Not available.
14.1. Timeliness
Indices are published approximately 45 days after the end of the reference month.
14.2. Punctuality
Indices are sent to Eurostat within 45 days after the end of the reference month.
15.1. Comparability - geographical
RPPI and ERPPI data are comparable across NUTS 2 regions while NRPPI data are comparable across NUTS 3 regions.
15.2. Comparability - over time
Data are comparable over time.
15.3. Coherence - cross domain
Other data relating to the housing market are obtained from internet advertisements. Index derived from this data set is used for internal reports and shows the same trend as the RPPI.
15.4. Coherence - internal
Due to different weight source and coverage (see 3.7.) RPPI is not calculated by taking weighted average of NRPPI and ERPPI. RPPI has an independent calculation process, thus RPPI does not always move between NRPPI and ERPPI (see 18.5.1. for detailed information).
OOHPI for Türkiye is not available.
Estimated annual cost for production of RPPI is approximately 150,000 EUR in total.
17.1. Data revision - policy
Due to late and/or revised submission of valuation reports, indices may be subject to revision up to one year.
17.2. Data revision - practice
RPPI data are revisable. Unperiodic revisions which stem from methodological changes are announced in advance.
18.1. Source data
See below.
18.1.1. Prices
Administrative data is used to compile the RPPI.
18.1.2. Weights
Data on house sales registered by the General Directorate of Land Registry and Cadaster (LRC) and average value of dwellings which are included in the CBRT dataset are used as weights for aggregating the strata in constructing the RPPI and ERPPI whereas building occupancy permit statistics issued by TURKSTAT and average value of dwellings are used for weighting in computing the NRPPI.
18.1.3. Source data - House Sales indicators
Not available.
18.2. Frequency of data collection
Data are collected monthly.
18.3. Data collection
Data are obtained by electronic databases.
18.4. Data validation
Various procedures ensure that errors are minimised in the data. The following validation checks are made on each record in the source data:
• Extreme values are identified and eliminated, • Data cleaning is done to remove cases of obviously erroneous data, • Minimum and maximum values are investigated, • Mass valuations are identified and eliminated.
18.5. Data compilation
See below.
18.5.1. Calculation and Aggregation
See below.
18.5.1.1. Index formulae
RPPI, ERPPI and NRPPI, which measure quality adjusted price changes are computed by estimating the regression coefficients for each period and each stratum. RPPI is not calculated by taking weighted average of indices for new and existing dwellings. Each of them has an independent calculation process. Indices are computed with the base year 2012 (2012=100) in the pre-2017 period and 2017 (2017=100) starting from 2017. The whole series are computed with the base year 2017.
18.5.1.2. Aggregation method
Price indices for individual stratum used in the aggregation procedure compare the current period prices to the average prices of whole 2017. Nomenclature of Territorial Units for Statistics (NUTS) is used for aggregating the data. The data are aggregated at the 3rd and 2nd levels of NUTS respectively for RPPI and ERPPI and the overall indices for Türkiye are constructed using the data aggregated at the 2nd level. NRPPI is constructed using the data aggregated at the 3rd level and the index for Türkiye is constructed using the data aggregated at the 3rd level. Data on house sales registered by the General Directorate of Land Registry and Cadastre (LRC) and average value of dwellings which are included in the CBRT dataset are used as weights for aggregating the strata in constructing the RPPI and ERPPI whereas building occupancy permit statistics issued by TURKSTAT and average value of dwellings are used for weighting in computing the NRPPI. Weights used to produce the RPPI and ERPPI are updated each year with the weights calculated using the average value and number of dwellings sold in the related stratum in the previous year. In calculating the indices for the very first years of the series, 2010 and 2011, data on average value of dwellings for 2010 and dwelling sales data for 2011 are used as an exception. Building occupancy permits issued in the two consecutive years preceding the reference year and previous year’s average value are used to calculate the weights for constructing the NRPPI. In calculating the weights for 2010, data on average value of dwellings for 2010 are used as an exception.
18.5.1.3. Derivation of sub-index and elementary aggregate weights
Data on house sales registered by the General Directorate of Land Registry and Cadaster (LRC) and average value of dwellings which are included in the CBRT dataset are used as weights for aggregating the strata in constructing the RPPI and ERPPI whereas building occupancy permit statistics issued by TURKSTAT and average value of dwellings are used for weighting in computing the NRPPI. Due to different weight source and coverage (see 3.7.) RPPI is not calculated by taking weighted average of NRPPI and ERPPI. RPPI has an independent calculation process, thus RPPI does not always move between NRPPI and ERPPI.
Weights used to produce the RPPI and ERPPI are updated each year with the weights calculated using the average value and number of dwellings sold in the related stratum in the previous year. In calculating the indices for the very first years of the series, 2010 and 2011, data on average value of dwellings for 2010 and dwelling sales data for 2011 are used as an exception. Building occupancy permits issued in the two consecutive years preceding the reference year and previous year’s average value are used to calculate the weights for constructing the NRPPI. In calculating the weights for 2010, data on average value of dwellings for 2010 are used as an exception.
18.5.1.4. Price updating
Weight reference period is t-1. Thus, there is no need to update the weights.
18.5.1.5. Chaining and linking method
No chaining is applied
18.5.1.6. Compilation of sub-indices
Hedonic method combined with geographical stratification approach is applied to produce RPPI, NRPPI and ERPPI
18.5.1.6.1. Hedonic method
RPPI, NRPPI, ERPPI which measure quality adjusted price changes related to the observed housing characteristics are constructed by using Laspeyres variant of the average characteristics hedonic method and log-linear regression model. The log-linear regression models are applied for each stratum and for each period which enables observing the price effects of quality component changes by stratum and in time. Dependent variable: Logarithm of appraisal value Independent variables: Gross area of use, quality of construction, year of construction, number of bedrooms, number of bathrooms, number of balconies, security service, heating, elevator, parking lot, swimming pool
18.5.1.6.2. SPAR method
Not available.
18.5.1.6.3. Stratification
In the scope of the current RPPI, ERPPI and NRPPI implementation, in which the geographical stratification approach is applied, 211, 211 and 89 homogenous strata are used respectively.
18.5.2. Other processing issues
See below.
18.5.2.1. Timing for pricing
Dwelling prices indicated in valuation reports prepared at the time of approval of individual housing loans are used as a proxy for price.
18.5.2.2. Treatment of VAT
VAT is included in the price of new dwellings.
18.5.2.3. Treatment of other taxes
Taxes other than VAT are not included in the price of dwellings.
18.5.2.4. Treatment of government subsidies
Not applicable.
18.5.2.5. Treatment of land
The price of land is neither included in prices nor in weights.
18.5.2.6. Housing cooperatives
Housing cooperatives are not covered in the RPPI.
18.5.2.7. Treatment of non-market transactions
"Non-market" transactions are not covered in the RPPI.
18.5.2.8. Treatment of multi-object transactions
Multi-object transactions are not covered in the RPPI.
18.5.2.9. Treatment of fractional transactions
Fractional transactions are not covered in the RPPI.
18.5.2.10. Outliers detection
The Tukey’s Hinges method has been implemented in the analysis of extreme values in order to construct the indices.
Unit prices that qualify the following equation:
m2 unit price < Q1-3*(Q3-Q1) or m2 unit price > Q3+3*(Q3-Q1)
where Q1: Lower Quartile and Q3: Upper Quartile are accepted as extreme values and excluded from the analysis.
18.5.2.11. Treatment of incomplete data source coverage
Not applicable.
18.6. Adjustment
No adjustments other than quality adjustment are applied to the RPPI data.
None.
Dwelling prices indicated in valuation reports prepared at the time of approval of individual housing loans are used as a proxy for price. Valuation reports which form a basis for housing loans are prepared by real estate appraisal companies. The actual sale of the property and utilization of the loan is not required and all dwellings appraised are included in the scope.
Following indicators are produced on a monthly basis:
Residential Property Price Index (RPPI)
Residential Property Price Index for New Dwellings (NRPPI)
Residential Property Price Index for Existing Dwellings (ERPPI)
Unit Price
26 January 2024
Residential Property Price Index (RPPI): Residential property price index constructed using hedonic regression method in which prices are adjusted for quality changes related to observed housing characteristics. Residential Property Price Index for New Dwellings (NRPPI): Price index constructed using hedonic regression method for dwellings built in the current and the previous years covering the whole country. Residential Property Price Index for Existing Dwellings (ERPPI): Price index constructed using hedonic regression method for the dwellings built before the current and the previous years covering the whole country.
Unit Price: Price calculated by dividing the value of a property by its gross area of use.
Appraisal values of dwellings.
The target population is the set of valuations of all types of dwellings prepared by real estate companies.
The RPPI and ERPPI, which are constructed to represent the whole country, cover appraised dwellings in 74 cities. While constructing the NRPPI, which also represents the whole country, data pertaining to the valuations of new dwellings in 51 cities where there are sufficient number of observations are used.
The national RPPI, ERPPI and NRPPI are weighted averages of the regional indices. RPPI is published for the whole country and on the basis of NUTS Level 2, whereas NRPPI and ERPPI are published for the whole country and for the three major cities.
Relevant month.
Not available.
Following units are used:
Index figures with reference to the year 2017 Annual and monthly percentage changes Unit prices in national currency (Turkish Liras)
See below.
See below.
Monthly.
Indices are published approximately 45 days after the end of the reference month.
RPPI and ERPPI data are comparable across NUTS 2 regions while NRPPI data are comparable across NUTS 3 regions.
