TurkStat  Necatibey Caddesi No 144 Bakanlıklar ÇANKAYA/ANKARA

Price Statistics Department

TurkStat,  Necatibey Caddesi No 144 Bakanlıklar ÇANKAYA/ANKARA

The harmonised index of consumer prices (HICP) is a consumer price index (CPI) that is calculated according to a harmonised approach. It measures the change over time of the prices of consumer goods and services acquired by households (inflation).

Due to the common methodology, the HICPs of the countries and European aggregates can be directly compared.

European classification of individual consumption according to purpose (ECOICOP)

The HICP covers the final monetary consumption expenditure of the household sector.

The main statistical variables are price indices.

The basic unit of statistical observation are prices for consumer products.

3.6.1. Statistical target population

The target statistical universe is the 'household final monetary consumption expenditure' (HFMCE) on the economic territory of the country by both resident and non-resident households. The household sector to which the definition refers, includes all individuals or groups of individuals irrespective of, in particular, the type of area in which they live, their position in the income distribution and their nationality or residence status. These definitions follow the national accounts concepts in the European System of Accounts.

3.6.2. Coverage error population

HICP does not have a deviation, and it represents the whole population. Weights are calculated from the expenditures of the whole population and prices are collected from every province of the country. No part of the population is excluded from the HICP.

3.7.1. Geographical coverage

The HICP refers to the economic territory of a country as referred to in paragraph 2.05 of Annex A to ESA 2010, with the exception that the extraterritorial enclaves situated within the boundaries of a Member State or a country are included and the territorial enclaves situated in the rest of the world are excluded.

3.7.2. Coverage error regions

Whole Türkiye is covered in the HICP calculation. Türkiye has 81 provinces and all of these provinces are included in HICP. No exclusion.

HICP is calculated by TurkStat and published by Eurostat only for Türkiye, not for the regions. But TurkStat calculates and publishes CPI for Türkiye and 26 regions. TurkStat does not publish HICP.

3.8.1. Start of time series

The HICP series started in January 1997.

3.8.2. Start of time series - national specifics

See the HICP database

2015=100

The following units are used:

• Index point
• Percentage change on the same period of the previous year (rates);
• Percentage change on the previous period (rates);
• Percentage share of the total (weights).

HICP is a monthly statistics.

Harmonised Indices of Consumer Prices (HICPs) are harmonised inflation figures required under the Treaty on the Functioning of the European Union. Regulation (EU) 2016/792 of the European Parliament and the Council of 11 May 2016 (OJ L 135) sets the legal basis for establishing a harmonised methodology for the compilation of the HICP and the HICP-CT.

This regulation is implemented by Commission Regulation (EU) 2020/1148 of 31 July 2020.

Further documentation, can be found in Eurostat’s website - HICP dedicated section, namely recommendations on specific topics, under the methodology page, and guidelines, under the quality page.

Not available.

Aggregated data of national CPI is released; however prices of elementary aggregate in outlets are not shared with anyone because of confidentiality.

Regulation (EC) No 223/2009 of the European Parliament and of the Council, of 11 March 2009, on the transmission of data subject to statistical confidentiality to the Statistical Office of the European Communities

Not available.

In line with the Community legal framework and the European Statistics Code of Practice Eurostat disseminates European statistics on Eurostat's website (see point 10 - 'Accessibility and clarity') respecting professional independence and in an objective, professional and transparent manner in which all users are treated equitably. The detailed arrangements are governed by the Protocol on impartial access to Eurostat data for users.

The HICP is released according to Eurostat’s Release calendar.

The calendar is publically available and published at the end of the year for the full following year.

Eurostat's website.

Users access the data from Eurostat web site.

Monthly

See next concepts.

A news release for the national CPI is available on TurkStat's website: http://www.turkstat.gov.tr.

No news release is published for the HICP.

Not available.

HICP Database.

Not available.

In TurkStat website: 

• ECOICOP 5-digit level weights for Türkiye,
• Indices in ECOICOP level 4 for Türkiye,
• Contributions of 12 main groups in monthly and annual rate of changes 

published as statistical tables and also available for public in the central dissemination system for national CPI.

The HICP Methodological Manual provides the reference methodology for the production of HICP. (https://ec.europa.eu/eurostat/web/products-manuals-and-guidelines/-/KS-GQ-17-015)

10.6.1. Documentation on methodology - national specifics

In Turkstat's website, all the methodological explanations about national CPI is available in the metadata. Also, any methodological changes in annual chaining procedure are released to the public with the first press release (January) of the national CPI. 

Not available.

Not available.

11.1.1. Quality management - Compliance Monitoring

Compliance Monitoring

11.1.2. Quality assurance - national specifics

Controls on the quality of the data:

Tablets have been used in price derivation step. All collected prices are reviewed by price collectors before being entered into the tablets. The second phase of control is incorporated in the computer program for data entry and in the end all data are manually checked by a person in the unit. If there are doubts about the reliability of one or several prices, these prices are checked once again by contacting price collectors or, if necessary, checked directly in the field.

In HICP calculations there are 3 phases of data analysis:

1. Control edits in tablet Pc (digit errors, '0' prices, explanations),

2. Control in regional offices (30 different queries, like max-min, outliers etc.)

3. Central office control after all data transfer

There is no automatic rejection of observed prices in our validation process. Each case (problematic price) is considered individually and all modifications are done on the basis of relevant information.

Confidence intervals, min-max values and outliers are used to evaluate the completeness and accuracy of the information. Moreover prices of items which have a high weight are examined. Also the results of indexes are calculated from two different programs (Excel and SAS (SQL format)) and these results are compared in terms of consistency before the calculation is finalised.

There is neither a Board of Advice nor Board of Users.

11.2.1. Compliance monitoring - last report and main results

Not available.

11.2.2. Quality assessment - national specifics

Not available.

In addition to being a general measure of inflation, the HICP is also used in the areas of:

• wages, social benefit and contract indexation;
• economic forecasting and analysis;
• measuring specific price trends;
• accounting purposes and deflating other series;
• inflation targeting by central banks;
• cross-country economic comparisons.

The euro area (evolving composition) index is used by the European Central Bank (ECB) as the main indicator for monetary policy management. The ECB and the European Commission's Directorate-General for Economic and Financial Affairs (DG ECFIN) use the HICP for assessing price stability and price convergence required for entry into European Monetary Union.

Other users include: National Central Banks, financial institutions, economic analysts, the media and the public at large.

12.1.1. User Needs - national specifics

Not applicable.

Not available

All Turkish ECOICOP indices at 5-digit level are produced but disseminated in Eurostat's website at 4-digit level only, due to our national rules.

TurkStat considers the accuracy of HICP to be high. Price collection assures good coverage and timeliness. Outlets, where prices are collected, are selected to represent the Turkish trade and services. The outlets are decided by using administrated data from the Ministry of Finance which consists of turnover data of the outlets in retail sector. All the private households in the economic territory are covered.

Numerical estimates of the HICP sampling error are not available because of using non-probability sampling.

HICPs non-sampling errors are not quantified. 

The full set of HICPs is published each month according to Eurostat’s Release calendar, usually between 15 and 18 days after the end of the reference month.

Each year, the January release is published at the end of February to allow for the annual update of the weights, both of individual product groups and the relative country weights of Members States in the country group aggregates.

The euro area flash estimate is published on the last working day of the reference month or shortly after that.

Since the March 1997, launch of the HICP release, the HICP for the country groups aggregates has always been published on the dates announced in Eurostat’s Release calendar.

HICPs across Member States aim to be comparable. Any differences at all levels of detail should only reflect differences in price changes or expenditure patterns.

To this end, concepts and methods have been harmonised by means of legislation. HICPs that deviate from these concepts and methods are deemed comparable if they result in an index that is estimated to differ systematically by less than or equal to 0.1 percentage points on average over one year against the previous year (Article 4 of Council and Parliament Regulation (EU) 2016/792).

Data on Turkish HICP are available with reference period 2015=100 starting from 1997.

There is no difference in terms of coverage of goods and services between the HICP and the national CPI. Games of chance and obligatory earthquake insurance items are included in CPI but not in HICP; ECOICOP is used in the HICP but COICOP-PPP in CPI; and base year 2015=100 in HICP but 2003=100 in CPI. These are the only differences between national CPI and HICP.

The HICPs are internally coherent. Higher level aggregations are derived from detailed indices according to well-defined procedures.

Not available

The HICP series, including back data, is revisable under the terms set in Articles 17-20 of Commission Implementing Regulation (EU) 2020/1148.

17.1.1. Data revision - policy - national specifics

In Türkiye the HICP and the national CPI are not revised.

HICP is not revised In Türkiye.

18.1.1. Weights

The HICP is calculated only for Türkiye, not for the regions and there is no adjustment in Turkish data. The expenditures from HBS are directly used with the Tourism Survey and Institutional population individual expenditure survey data.

The weight data from the HBS survey is at item variety level.

Tourism Survey and Institutional population individual expenditure survey data do not have detail at sub-index level. HBS data give the entire expenditure pattern in item variety level to main expenditure groups level.

The weight structure is detailed in item variety level for all 26 regions. Outlets do not have weight in CPI or HICP weight structure.

The weight data is taken from HBS and updated every December. In 2023, for 404 items and 895 item varieties weights’ HBS data is used as main source.

Every year from elementary (item variety) level to main expenditures groups, the weight structure is reviewed.

18.1.1.1. Compilation at elementary aggregate level

The HICP is calculated only for Türkiye, not for the regions and there is no adjustment in Turkish data. The expenditures from HBS are directly used with the Tourism Survey and Institutional population individual expenditure survey data.

The weight data from the HBS survey is in item variety level.

Tourism Survey and Institutional population individual expenditure survey data do not have detail at sub-index level. HBS data give the entire expenditure pattern in item variety level to main expenditure groups level.

The weight structure is detailed in item variety level for all 26 regions. Outlets do not have weight in CPI or HICP weight structure.

The weight data is taken from HBS and updated every December. In 2023, for 404 items and 895 item varieties weights’ HBS data is used as main source.

Municipality buses and water fees have equal fees at the item-variety level.

Every year from elementary (item variety) level to main expenditures groups, the weight structure is reviewed.

Internet and phone call fees (not mobile) are derived by using single observation. The weight structures are formed by using administrative data.

18.1.1.2. Compilation of sub-index weights

TurkStat uses HBS as the main data source in every level of the COICOP from item variety level to the 12 main expenditure groups. Tourism and Institutional population individual expenditure survey expenditures are added in the 12 main groups. HBS (t-2, t-3 and t-4) expenditures are price-updated to December of year t-1. The price update process is carried out at COICOP 5-digit level. 

Up to 2020, the procedure mentioned above was applied. For 2023 weights which are used in index calculations, the expenditures of HBS data (2017, 2018, 2019) are updated to 2022 (because of the COVID-19 pandemic) in line with the methodological note published by Eurostat on 3 December 2020. This update process was performed by using the development rate of national accounts expenditures data between 2021 and 2022. National accounts department prepared the file with the estimation of the 4^th quarter of 2022 (the same procedure was applied for the years 2020 and 2021).   

18.1.1.3. Compilation of sub-index weights

HBS expenditures covers t-2, t-3 and t-4 values. Expenditures from t-3 and t-4 are updated to t-2. Tourism and Institutional population individual expenditure survey data also reflects the year t-2. Finally, all these expenditures are price-updated to the December of the year t-1.   

18.1.1.4. Weights – plausibility checking

Every year the weight system is reviewed and calculated. Every year the values found are compared with the previous years. If there is significant rise or fall in items weight, these item weights are controlled in detail.

18.1.1.5. Price updating

Price-updating to the previous year's average price level is not carried out.

Price-update is carried out to the last year’s December price level

Price-updating practice is not applied at elementary aggregate levels, it is processed at COICOP 5-digit level

All data from HBS t-3 and t-4 are carried out to t-2; Tourism survey and Institutional population individual spending survey (belong to t-2) are price-updated to the December of the previous year (t-1) at 5-digit level. In this process the ratio of the index number in December of the previous year to the average of index numbers of 12 months of the year t-2 is used for COICOP 5-digit codes. The lower levels are not updated.

In 2023 the HBS data (2017, 2018, 2019) were price-updated to 2022 by using the development rate of the national accounts expenditures between 2021 and 2022. Since the updated data reflect the year 2022, the ratio of the index number in December of 2022 to the average of index numbers of 12 months of the year 2022 was used to update data to December 2022.

18.1.1.6. Compilation of total household final monetary consumption expenditure

HBS data is used in every level of COICOP classification to determine the item weights used in HICP calculation. Normally the HBS data is updated from t-2 to the December of the previous year. The HBS data (2017, 2018, 2019) had to be updated to 2022 to reflect the conditions in the country. According to the methodological note published by Eurostat on 3 December 2020, the national accounts department prepared a file that shows the development rates of expenditures between 2021 and 2022. The file prepared was in COICOP 5-digit level. The item variety level expenditures of the HBS data are updated with the rate (related 5-digit rate) calculated from national accounts data. The national accounts department prepared the development file by estimating the 4^th quarter of the year 2022. 

18.1.2. Prices

The main data for HICP is the data from traditional compiling by tablet pc. Also some administrative data is used for checking the prices.

18.1.2.1. Data Source - overview  

The main data for HICP is the data from traditional compiling by tablet pc. Also some administrative data, scanner data and web scraping data are used for calculations.

18.1.2.2. Scanner data - general information

From the end of 2018 to 2021, TurkStat got scanner data from leading chain markets and during this period made the necessary controls on these data. Up to 2021 the scanner data was not used in index calculations. In 2021, TurkStat started to use the scanner data prices in index calculations, also still using in 2023. 

18.1.2.3. Web scraping - general information

In 2020 to 2021, TurkStat started to study on implementing web scraping in HICP calculations. From the beginning of 2022, web scraping data started to be used in index calculations. Web scraping (average of online prices for each item variety level) has been used instead of field survey prices. Several studies (classification, code matching, etc.) were carried out to make the data ready for CPI calculations.


For the prices of household appliances (refrigerator, washing machine, dishwasher etc.), electronic products, clothing, furniture, new cars and bus tickets that are suitable to price by web scraping in terms of item definitions, the prices compiled over the Internet will be used in CPI calculations in 2023. The number of prices to be obtained by this method constitutes approximately 5.3% of the total number of prices to be compiled.

18.1.3. Sampling

18.1.3.1. Sampling design: locations for survey

18.1.3.2. Sampling design: outlets

18.1.3.3. Sampling design: newly significant goods and services

The main source of newly significant goods and services is the HBS data. Other data sources like regional office’s advice, price collectors’ information, market researches information, etc. is also used in the process of determining newly significant good and services.

New products are entered in the index in December of every year.

• 2023: tights for women
• 2022: no new item added.
• 2021: pickle, women sweatshirt
• 2020: range hood, children leggings
• 2019: Prepared meat dishes, canned fish, ready-made milky sweets, dill, Spearmint, rocket, cress, hazelnut butter, dress for child, food expenditure for pets, watch, bag for women
• 2018: ice tea, men's anorak jacket, bed pique set
• 2017: roller curtain, freezer, test book
• 2016: dress (single piece), steak tartar a la turca, pizza, attorney fee
• 2015: game console13

Price data is collected every month.

18.3.1. Price collection surveys

For field survey prices: Prices are compiled by price collectors in regional offices. Only small group of items’ prices like 'Fee for cellular phone calls and Electricity fee' are collected by the central office. All data entry process take places in regional offices. Modern tablets have been used directly in price compiling step since the beginning of 2016. Actual rental prices are collected using Computer Assisted Telephone Interviewing method (CATI) by the responsible group in the central office, since the beginning of 2018. 50.4% of total prices collected by field survey and traditional prices collection.

For scanner data: From the beginning of 2021, scanner data started to be used in calculations. 44.3% of total prices derived from scanner data.

For web scraping: From the beginning of 2022, web scraping started to be used in calculations. 5.3 % of total prices derived from scanner data.

18.3.2. Timing of price collection

Prices are collected on a monthly basis.

For field survey prices: 1-31 prices

For scanner data: 1-24 prices collected because of the dissemination date of national CPI (3rd of every month).

For web scraping: 1-24 prices collected because of the dissemination date of national CPI (3rd of every month).

Data validation has many different stages.  Validation, such as for quantity errors, starts in tablet PCs that price collectors are using. Secondly, there are several queries on the data after transmission of data to the database such as, time series, max-min price controls. Thirdly, a final validation made by central office staff item by item before closure of data set. All details given in the lower sections.

18.4.1. Data validation - price data

Tablets are used for price compilation in TurkStat. Raw data is controlled in tablets first.

• Checking empty prices
• Checking high price increases or decreases.
• Checking quantity errors

In addition to the control process in tablets there are some pre-prepared queries for checking similar types of errors after transmission of data to the database (this process takes place in regional offices first, then in the central office). After the initial checks are completed by regional offices, a second stage of control process starts in the central office. If any error is detected by the central office, then regional offices are informed about errors to check. Correction is made in the tablets and the whole process starts over if needed.

Pre-prepared queries are used for checking consistency of the price information. Checks being carried out by central and regional offices are given below.

• Time series control: item by item
• Max-min price control in same elementary aggregate.
• Confidence interval control for prices in same level of elementary aggregate
• Control of rate of price changes for single item and elementary aggregates.

There is no automatic rejection or adjustment of observed prices in our validation process. Each case (problematic or extreme prices or price changes) is considered individually and all modifications are on the basis of relevant information. If there are doubts about the reliability of one or several prices, these prices are checked once again by contacting price collectors and checked directly in the field if necessary. The reason for price change has to be explained by price collectors.

18.5.1. Elementary price index formulae

The HICP is calculated using Laspeyres-type chain index covering ECOICOP.

The Jevons formula is used the HICP. The price indices for elementary aggregates are calculated as a ratio of geometric mean prices for each statistical region.

Weights for calculating the index in a given year are based on the data from the HBS data which comes from t-2, t-3 and t-4 years results and price-updated to December t-1 for every year. These data are also supplemented and verified using other statistical (Tourism survey and Special survey for institutional population) and non-statistical sources.

Alternative formula is not used.

Scanner data is not used.

Number of decimals:

• Price observations: 4 decimals.
• Weights: full (unrounded)
• The compilation and transmission of index figures and rates of change: full (unrounded)
• For publication of index figures and rates of change: 2 decimals

There is no specific rounding formula. Published index numbers are rounded automatically by SAS and Excel.

The elementary aggregates are calculated as ratio of the geometric mean of prices for each statistical region (there 26 regions in Türkiye). After the calculation of geo-mean of prices on regional elementary aggregate base, national prices on elementary aggregates are calculated using regional weights.

18.5.2. Aggregation of different data sources

SAS and Excel are used in the calculation and control process of HICP/CPI.

After the online transfer of price data from tablets to the database, SAS query results transfer to Excel sheets to control.

18.5.3. Chaining, linking and splicing methods

The index numbers of December are set equal to 100 every year. December is the linking month. HICPs for Türkiye are available from 2004 (earlier figures are estimates based on the national CPI). Current base year is 2015=100.

18.5.4. Quality adjustment – Detailed information

The following quality adjustment methods are used:

• Direct comparison (when judged to be no difference in quality between the old and new items),
• Quantity adjustment (proportional, when the only difference is in the quantity included (package size), usually a small difference),
• Overall mean imputation (= bridged overlap, when the quality difference cannot be estimated),
• Expert judgment (where a well-justified opinion can be obtained from a seller or outside expert),
• Option pricing (50% of the most recent price of the option bought separately – mostly used for new cars),
• Overlap (occasionally, and less than in previous years; this method is intended to be restricted to goods in the same phase of their life cycle).

When the first price of the new product-offer is unusually high the bridge overlap method is used.

18.5.5. Seasonal items

Some items in groups 'Fresh fruits and vegetables' are clothing and footwear are accepted as seasonal items. 

We do not treat fish and package holidays as seasonal for the reasons listed below:

• There are package holidays available during 12 months and hotels as well. For this, reason it does not show seasonality.
• We use the type of fish that is most consumed by consumers in the index calculations and also compile almost the same fish price level. There are many varieties of fishes and there are differences between regions. Thus, there is not seasonality on fishes.  

Not applicable.