National Statistical Institute of Austria

Department for macro-economic statistics

Guglgasse 13
1110 Vienna
AUSTRIA

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

None.

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

Price collection is carried out in 19 regions. Prices may be collected in the immediate surroundings of these cities if shopping centers and the like are deemed important. There is no local price collection outside these 19 cities which, by themselves, cover 40 % of the Austrian population, or more if suburbs are included. The 19 regions include the 14 biggest cities in Austria. The smallest city in which prices are collected has 11,000 inhabitants.

For hotels, accommodation and insurances the prices are collected locally, also in rural areas, by the central staff. Items which have unique prices in the whole country or are difficult to collect for some reason are also collected centrally.

3.8.1. Start of time series

The HICP series started in January 1997.

3.8.2. Start of time series - national specifics

See Database - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu)

The Austrian HICP series start in January 1996. 

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.

None.

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.

According to policy rules (see 7.1).

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.

Release calendar - Eurostat (europa.eu).

Data is published on the webpage of Statistik Austria (www.statistik.at) in German and English. The main results of CPI and HICP are available as HTML, Excel or PDF files. More detailed data are available for a fee from the statistical database StatCube. Special aggregates and longer time series are available too. Further data and special aggregates can be requested via telephone, email and the HICP database (see point 10.3).

Monthly.

Monthly regular press release in German and English. The press release is send to the press, press release subscribers and special users. The service is for free. Detailed data tables (ECOICOP 5 and lower, and older time series) can be requested regularly for a small monthly fee. All data are available on our website via StatCube and additional data as pdf or ods tables. The CPI rates and index levels are published with one decimal. 

Monthly regular press release in German and English. The press release is sent to the press, press release subscribers and special users. The service is for free. Detailed data tables (ECOICOP 5 and lower, and older time series) can be requested regularly for a small monthly fee. 

Statistik Austria disseminates the Austrian HICP at the same time as Eurostat publishes HICP data. The Austrian HICP data are published as preliminary in t+1. The final data are published in the following month (t+2). 

Database - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu).

Microdata is available under certain conditions for scientific purposes. The data is anonymised, bound to a certain topic and must be deleted after the research purpose is fulfilled. 

See also Overview - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu).

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

Methodological articles regarding the Austrian HICP are available in the monthly 'Statistische Nachrichten' published by Statistik Austria.

The latest comprehensive methodological update is described in 'VPI und HVPI-Revision 2020, Neuer Warenkorb und Gewichtung' — Statistische Nachrichten 05/2021.

A standardised document that explains the CPI production in depth is only available in German: 'Die Standarddokumentation des Verbraucherpreisindex und Harmonisierten Verbraucherpreisindex'.

Regular compliance monitoring visits by Eurostat, documentation available at the webpage Quality - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu)

Controls on the quality of the data

Checks are carried out at many levels and in several steps. For example, extreme price changes are identified and verified. Price movements for Elementary Aggregates (EAs) all the way up to the all-items index are checked. The full aggregation is repeated up to seven times in this process.

There is no automatic editing. Local price collectors are contacted frequently to confirm price observations. This results occasionally in a revision of a price observation, either immediately or in the following month.

 The quality of the HICP can be assumed to be very high. Its concepts and methodology have been developed according to international standards and using consumer price statistics experience from all EU Member States. HICPs are considered to be sufficiently accurate for all practical purposes they are put into. In particular it is the best measure of inflation for the euro area and European Union as a whole as well as for the comparisons of inflation across countries for which it is compiled. The indices are disseminated around mid-month following a predetermined timetable.

Further work is ongoing to improve the quality and in particular the comparability of the index. Key priorities are the treatment of owner-occupied housing (currently excluded) and greater harmonisation of methods for quality adjustment and sampling. 

The available compliance or follow-up reports can be found in the dedicated HICP section 'Compliance Monitoring' of Eurostat’s website, under 'Quality - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu)'.

11.1.1. Quality management - Compliance Monitoring

 Compliance Monitoring

11.1.2. Quality assurance - national specifics

Controls on the quality of the data

Checks are carried out at many levels and in several steps. For example, extreme price changes are identified and verified. Price movements for Elementary Aggregates (EAs) all the way up to the all-items index are checked. The full aggregation is repeated up to seven times in this process.

There is no automatic editing. Local price collectors are contacted frequently (100-200 times per month) to confirm price observations. This results occasionally in a revision of a price observation, either immediately or in the following month.

11.2.1. Compliance monitoring - last report and main results

Eurostat's compliance and follow-up reports can in the webpage Quality - Harmonised Indices of Consumer Prices (HICP) - Eurostat (europa.eu)'.

Direct link to 2021 follow-up report.  

11.2.2. Quality assessment - national specifics

The quality of the HICP can be assumed to be very high. Its concepts and methodology have been developed according to international standards and using consumer price statistics experience from all EU Member States. HICPs are considered to be sufficiently accurate for all practical purposes they are put into. In particular it is the best measure of inflation for the euro area and European Union as a whole as well as for the comparisons of inflation across countries for which it is compiled. The indices are disseminated around mid-month following a predetermined timetable.

Further work is ongoing to improve the quality and in particular the comparability of the index. Key priorities are the treatment of owner-occupied housing (currently excluded) and greater harmonisation of methods for quality adjustment and sampling. 

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

Main users are the ECB and national bank, Austrian ministries, public and private users (political decisions, indexation, price data analysis, etc.).

There is a Board of Users which gives input and opinions about the use of the CPI index and changes in price collection, methodology and new projects. The Board can give assistance and opinion, but not instructions. The meetings take place twice a year. The agenda is given by the CPI/HICP prices team. Special topics can be put on the agenda on request of the participants. Most topics concern the CPI as well as the HICP as the discussions are mostly about details in the price collection or quality adjustments.  

The HICP is complete compared to relevant regulations/guidelines.

The accuracy of HICP is generally considered to be high. The accuracy of source data is monitored by assessing the methodological soundness of price and weight sources and the adherence to the methodological recommendations. There is a variety of data sources both for weights (National Accounts data, Household Budget Survey data, etc.) and prices (visits to local retailers and service providers and central collection via mail, telephone, e-mail and the internet are used). The type of survey and the price collection methods ensure sufficient coverage and timeliness. The outlets, from which prices are collected, are chosen to represent the existing trade and services network and they are based usually on three main criteria: popularity with consumers; significant turnover from consumer sales; and availability of goods and services included in the HICP basket. All the private households in the economic territory of the country are covered, whether resident or not and irrespective of their income.

Furthermore, Eurostat and the Member States are actively following up an Action Plan concerning quality adjustment and sampling issues. Concrete best practices have been agreed for a range of specific goods and services (in particular cars, consumer durables, books, clothing and computers).

The sampling errors are reduced by using a sample of consumer prices that is as large as possible, given resource constraints. A model that optimises the allocation of resources by indicating the number of prices that should be observed in each geographic area and each item category is used, in order to minimize the variance of the all-items index.

For the HICP non-sampling errors are not quantified. They are reduced through continuous methodological improvements and survey process improvements, which can help avoiding coding and typing errors.

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.

HICP data are fully comparable over time. There have been several improvements in methodology since HICP was introduced with the aim of improving reliability and comparability of the HICP. These changes may have introduced breaks in time series. However back calculations under the newer standards were performed when appropriate basic data was available.

Differences between the HICP and national CPI

The following expenditure is included in the HICP but excluded from national CPI: consumption expenditure of non-residents in the economic territory.

The following consumption expenditure is included in the national CPI but excluded from HICP: Games of chance, road taxes and insurance for owner-occupied housing are included in the national CPI, but excluded from the 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

The published HICP data may be revised for corrections, and new or improved information.

The CPI data is preliminary when first released and final when the data of the following month is published for the first time (t+15/ t+45).

18.1.1. Weights

For the detailed basket of goods and services please refer to Statistik's Austria webpage 'Consumer price index (CPI/HICP) - STATISTICS AUSTRIA - The Information Manager (statistik.at), under 'further data'.

****

a. Describe in general terms the weights used below the sub-index level:

The weights used at elementary aggregate level are based on the HBS and are accompanied by turnover and transaction data as well as studies about consumer behaviour and several official statistics.

b. What is the lowest level of aggregation (number of digits) where explicit weights are introduced?

Single code level, which is the level below 5-digit.

c. If only HBS is used, are there cases where the weights are adjusted? How do you carry out adjustments? Provide the rationale for these adjustments

Transaction data and turnover data is used to accompany the HBS data set.

d. If multiple sources are used, explain which the main ones are and how they are combined.

Several sources are related to the economy like company data, market shares, consumer behaviour or scientific studies.

 
e. What is the frequency of update of weights applied at the elementary aggregate level?

Annually

f. What is the source for weights for regions?

The HBS and turnover data as well as data from the tourism statistics.

g. What is the source for weights for outlets? What is the source for weights for products?

Outlets and products are not weighted specifically.

18.1.1.1. Compilation at elementary aggregate level

a. Describe in general terms the weights used below the sub-index level:

The weights used at elementary aggregate level are based on the HBS and are accompanied by turnover and transaction data as well as studies about consumer behaviour and several official statistics.

b. What is the lowest level of aggregation (number of digits) where explicit weights are introduced?

Single code level, which is the level below 5-digit.

c. If only HBS is used, are there cases where the weights are adjusted? How do you carry out adjustments? Provide the rationale for these adjustments

Transaction data and turnover data is used to accompany the HBS data set.

d. If multiple sources are used, explain which the main ones are and how they are combined.

Several sources are related to the economy like company data, market shares, consumer behaviour or scientific studies.

 
e. What is the frequency of update of weights applied at the elementary aggregate level?

Annually

f. What is the source for weights for regions?

The HBS and turnover data as well as data from the tourism statistics.

g. What is the source for weights for outlets? What is the source for weights for products?

Outlets and products are not weighted specifically.

18.1.1.2. Compilation of sub-index weights

In general, for the compilation of weights in 2023, national accounts data for the year 2021 have been used and consequently adjusted by the rates of change of available subclass data and estimates for private consumption expenditures in 2022.

The value of private expenditure was determined for calculating the global HICP weights. In those groups in which the data was taken from the National Accounts, the domestic National Account concept could be used without any further transformations. Where data from the HBS was used, the results were converted with the help of the balance of payments data to the domestic concept. The output share of tourists has been added to the results of the consumer survey. In addition, the net concept of insurance was used and the owner occupied housing in the HICP has been omitted. In the third step the aggregates were divided up on the individual items. This was carried out with the results of different data sources: the HBS, the trade register, administrative data and other suitable secondary sources.
On lower level than COICOP 4-digits the HBS information was used to calculate the weighting of the items. If there were information about a change in consumption or consumer behaviour, this was respected in the creation of the single item weights.

Weights compilation at elementary aggregate level
For the determination of the expenditure volume for the HICP weights on 4-digit level the values are used for t-2 from the National Accounts.
The group totals of the HICP individual items were allocated in the ratio of the HICP single item weights of the previous year. Thus, the new single item weights were calculated. For some COICOP 4-digits adjustments for the group sums or item weights were necessary. Where the information from the National Accounts in t-2 did not prove to be representative, internal analyses, additional analyses from the National Accounts, information from secondary sources or administrative data were used.
Fixed absolute amounts from various sources, mainly from National Accounts, are used for prescription fees, for the E-card fee, care and retirement homes,  gasoline, diesel fuel, motor oil, flight ticket, TV, cable cars, television fee, tuition fees and other public tariffs.

Weights below the 4-digits COICOP (5-digits and national elementary aggregates) were derived from additional data sources, like the Household Budget Survey, market data or administrative sources.

Sub-index weights are based on national accounts data for the year t-2 which are adjusted to make them representative for t-1. The main data source for the adjustment are the quarterly national accounts data of the rate of change of private consumption of the year 2022. These are mainly compiled using STS business statistics (in particular retail and trade) and advance turnover tax return data, but also recent data and estimates of different national data sources like company data, administrative sources, community fares, census data, national statistics and similar data sources. All data stems from 2021 or 2022.

We used estimates from quarterly national accounts of the rate of change of private consumption in the 4^th quarter of 2021 and supplemented the available data of the first three quarters in 2022 to attain a yearly rate of change for the most important subclasses

The 4^th quarter 2022 is an expert guess.

18.1.1.3. Compilation of sub-index weights

National Accounts data t-2, HBS data latest available (2019/2020)

The data for private consumption in National Accounts are always published in Austria in the middle of the year. The period of reference is 't-2'. That means the National Accounts information published during summer 2022 is based on data from 2021 and enters the HICP in January 2023. Individual data sources, which are necessary to calculate the private consumption in National Accounts, are not available over the entire period from January until December. In this case calculated adjustments are carried out to smooth the reference time period (e. g. economic surveys). The National Accounts generally follows the accrual principle. This means that transactions are attributed to the periods in which they economically occurred. Data sources with divergent financial years and divergent survey periods other than the calendar year will be adapted to suit the accounting periods. Data from the HBS were used for the allocation of detailed weights below the ECOICOP 4-digit level. The survey is carried out in 5-year intervals. The HBS is the main source for the weights of the elementary aggregates. The data is updated every year and adapted with suitable secondary sources if necessary. Adjustments are primarily necessary for technical equipment and tariffs and charges, if the national legal basis changes. Secondary sources are selected to fulfil the criteria of representativeness and timeliness.

18.1.1.4. Weights – plausibility checking

Weights are checked for plausibility by using additional public or private data like turnover and sales data, and other statistic sources like the tourism statistics. 

18.1.1.5. Price updating

Price updating is done every year in December for the weights of the next year.

According to the harmonised approach set by Eurostat and agreed upon by Member States, Statistik Austria applies a price-updating procedure when compiling the HICP weights at the beginning of each year.

Price-updating is carried out after the finalisation of the yearly weight compilation.

The price-updated weight of each elementary aggregate i for the year t (Wi,t(new):) is calculated by multiplying the elementary aggregated weight Wi,t−1(old) with the ratio of the index value of the elementary aggregate i in December of previous year (t-1) and the mean of the Index values of the elementary aggregate i in the previous year (t-1).

After price updating, all weights Wi,t are standardised to ΣWi,t=100. Subsequently all standardised weights Wi,t are rounded to 5 decimals using a sum preserving rounding formula to assure that the sum of all rounded weights stays 100.00000.

The development of weights are monitored and benched against recent sales volume developments of product groups whose index is influenced by QA (e.g. processing equipment). Statistik Austria may take measures to assure that the price updating procedure does not lead to results that contradict obvious market developments of a product group.

No price updating is applied from t-2 to t-1.

The price-updating to December t-1 is conducted as follows: the single item weights of each year are divided by their annual average index number of that year and multiplied by the index number of December of the respective year.

The price-updating is applied at single item level.

18.1.1.6. Compilation of total household final monetary consumption expenditure

Compilation of country weights

Data sources and adjustments made to estimate the total Household Final Monetary Consumption Expenditure (HFMCE) needed to compute the country weight:

The HFMCE is calculated from the individual consumption expenditure by households minus narcotics, imputed rentals for housing, games of chance, prostitution, life insurance, health insurance, FISIM, net purchases abroad and pensions. These items were adjusted with factors from the quarterly national accounts statistic of import/exports statistics, microcensus, games of chance turnovers, growth rate of insurance premiums, FISIM growth rate and the balance of payments.

The 4^th quarter of t-1 is based on an early estimation of the rate of change of the national accounts’ private consumption by the Austrian national bank.

Data which were not available for the 4^th quarter of t-1 were completed with an expert guess.

18.1.2. Prices

Data sources of prices: companies' data, administrative sources, community fares, census. 

**

Price collection is organized in two ways: central price collection by Statistik Austria staff via telephone, email, fax and internet, and staff visits to the biggest shopping mall in Austria. Regional price collection is done by 19 regions, which are spread all over Austria and guarantee a regional representativity of price developments.

There are more than 80 price collectors in 19 regions in Austria, which are mainly municipal employees. In addition, Statistik Austria employs staff members for the central price collection. 

Total number of prices per month: about 42 000

**

Scanner data was used for index production during several months of the year 2020 and beginning of 2021 due to the Covid19 restrictions. The usage covered several ECOICOPs, notably 01, 02.1 and 12.1.3. The data was analysed for the monthly rate of change of all index-relevant products. Regular usage of scanner data for COICOP 01, 02.1 and 12.3.1 started with the index for January 2022.

**

Web scraping is used to collect data for new rents and mobile phone tariffs, as well as other information not directly entering price indices. 

18.1.2.1. Data Source - overview  

Data sources of prices: companies, administrative sources, community fares, census. 

18.1.2.2. Scanner data - general information

Scanner data was used for index production during several months of the year 2020 and beginning of 2021 due to the Covid19 restrictions. The usage covered several ECOICOPs, notably 01, 02.1 and 12.1.3. The data was analysed for the monthly rate of change of all index-relevant products. The general use of scanner data for ECOICOPs 01 (Food and non-alcoholic beverages), 02.1 (Alcoholic beverages) and 12.1.3 (Other appliances, articles and products for personal care) is implemented starting with the index for January 2022.

18.1.2.3. Web scraping - general information

Web scraping is used to collect data for new rents, clothing and mobile phone tariffs, as well as other information not directly entering price indices. 

18.1.3. Sampling

18.1.3.1. Sampling design: locations for survey

As the sampling of products and outlets is based on the principle of representativeness (which means cut-off samples) and not by random sampling, an accurate sampling error cannot be evaluated. 19 regions are covered, plus additional postcode areas for scanner data.

18.1.3.2. Sampling design: outlets

Outlets are selected for every consumer price relevant trading, service and business branch. The business register and market research studies are used as supplementary information. The representative sample of sales outlets considers both the representation of important nationwide outlets, as well as those of regional importance. A representative point of sale is a business that represents the local consumption pattern and has the appropriate range of items.

The choice of regional outlets is done in collaboration with the regional price collectors, and the regional Chamber of Commerce, representing an important input for Statistik Austria due to their knowledge of local conditions. 
The sampling has to take into account the representativeness in terms of type of industry (for example butcher, bakery, petrol station, etc.) and type of outlets (for example department store, supermarket, discount store, specialty store, etc.).

Outlet selection is based on data of the Business Register. Only outlets with significant amounts of sales volume are chosen for the price collection. Prices of commodities are collected in about 4,000 outlets, so that retail trade is well represented. If an outlet closes or becomes irrelevant, another representative outlet (with respect to turnover) is selected. Outlet weights are not used. The weighting is based implicitly on the number of outlets in the sample.

The outlet sample is generally updated every five years, when necessary even more often if there are obvious changes in the market.
Market stalls, mail order and internet shopping are included in the price collection.

Prices for petrol are available from the Ministry of Finance on a weekly basis. 

18.1.3.3. Sampling design: newly significant goods and services

The introduction of the chain index allows changing of the basket of goods and services every year if necessary. Prices of newly significant goods and services enter the index in December of the previous year.

Price data is collected every month.

18.3.1. Price collection surveys

Prices are collected in about 4,000 outlets in Austria. The survey is done via fax, email, by personal visits in the shops or by telephone. Standardised survey questionnaires are used for different types of shops and services.

Some prices are also collected online  (for example flights, accommodation, mobile phone tariffs, electronics or clothes).  

18.3.2. Timing of price collection

Prices are usually collected monthly in the week between 6th and 12th. Fuel prices are collected four times a month. Scanner data is also collected weekly, with the sum of transactions of the previous week.

Data validation is done by Statistik Austria; additional quality checks are carried out also by Eurostat.

18.4.1. Data validation - price data

Price data is checked for inconsistencies. First by the tablet program which detects outliers, then by a manual plausibility check, and in a third stage when the basic index numbers are calculated.

The data is automatically checked for obvious errors. Checks are performed against previous months with respect to various criteria: missing or substantially changed data from specific shops, missing price observations or extreme price changes. Prices that seem inadequate are checked again with the source of data. If an error occurs, the price is corrected, or, if the price proves right, it enters the index. 

18.5.1. Elementary price index formulae

Laspeyres / chain index.

The index is calculated using a Laspeyres chain index with weights that are adapted on a yearly basis. The base year is 2015 for HICP and CPI. For CPI, the base year 2020 is also available starting from January 2021.
The elementary aggregates are calculated as a ratio of the geometric mean of prices (GM) per item per region. It is an average of price data. The reference price of the current month is compared to the price of the base period, which is the price of the item in December of the previous year (due to the chain index calculation). If the quality of the item changes during the price observation period, quality adjustments are done.

The geometric mean is used as the elementary aggregate formula.

After the calculation of the elementary aggregates on a regional basis, the aggregates are weighted by special regional weights to obtain a national elementary aggregate. Each of the 19 price collecting regions has a specific weight that is kept constant for some years and sums up to 100 for the main index for Austria. As a result, 756 (for CPI) and 743 (for HICP) indices are produced, one for every item in the basket of goods and services. These index numbers are aggregated to a CPI and HICP for Austria.

The calculation is done with full digits of the index numbers. Publication is done with two decimals for HICP and one decimal for the CPI. 

18.5.2. Aggregation of different data sources

The price collection and calculation is performed with a central data base for price collection and quality adjustments. A statistical program performs the aggregation of elementary indices to regional indices and the yearly chaining.

The index numbers of December are set equal to 100 every year to perform the index chaining. The rate of change for the current month is computed from the index number of the current month divided by the index number of previous December (=100). The result is the adjustment factor (ADF). The ADF is multiplied by the index number with the base 2015=100 of the previous December to obtain the new index number with the base 2015=100 (HICP) for the current month. The indices are weighted. 

The HICP is calculated as a chain index since the year 2000 (current base year is 2015=100). The CPI is a chain index since the year 2011 with December 2010 as the first chain month. The latest CPI is based on 2020=100.

18.5.3. Chaining, linking and splicing methods

Please refer to the Standarddokumentation (in German) under http://www.statistik.at/web_de/statistiken/wirtschaft/preise/verbraucherpreisindex_vpi_hvpi/index.html 

18.5.4. Quality adjustment – Detailed information

In the year 2021, 3.6 percent of all prices were subject to a quality adjustment (QA). Most QAs were applied in ECOICOP 03 ('Clothing and footwear') due to the rapid change of product models and the domination of seasonal products in this division, followed by ECOICOP 09 ('Recreation and Culture') where the supply of best-selling books, DVDs and CDs change on a monthly basis also requires many QA. Also ECOICOP 08 ('Telecommunication') faces fast changing product offers, mostly in the segment of electronic devices for telecommunication, which make QAs necessary.

Most used QA methods are quantity adjustment (e.g. for food), expert judgment adjustment method (e.g. for clothing), option pricing method (e.g. for durables and cars), and hedonic repricing method (for books and memory cards/sticks)as well as hedonic time dummy method (for female clothing-data gathered online, and mobile tariffs).

Quality adjustments in percentage of all prices in the relevant COICOP-groups for the year 2022:

18.5.5. Seasonal items

The standards for the treatment of seasonal items were introduced into the HICP and CPI calculation in September 2011, and are in accordance with article 14 of Commission Implementing Regulation (EU) 2020/1148. A parallel calculation of the HICP index with and without the implementation of the seasonal adjustment between September 2011 and September 2012 showed a difference between 0.1 and -0.1 percentage points in the year on year rate of change of the All-items HICP. In eight out of thirteen months, the difference was zero.

The seasonal adjustment takes effect in the following COICOP groups:

For seasonal items a fixed weights approach is used and two estimation procedures are applied: all seasonal and counter seasonal adjustment. For the counter seasonal adjustment two variants of the same product are used (e.g. a winter and a summer basket for clothes) and the price development is estimated by the available price observations. The all seasonal procedure is used for goods where no counterpart for the off-season is available. For these products (e.g. some fruits) the average price of the product of the previous in-season months is inserted in the first month and the price development of all other products in the same ECOICOP class are used to estimate the index in the off season months. For a minority of products which would not be available at all in Austria the last observed prices are fixed (e.g. closed schools and theatres in summer or public baths that are closed during winter) until the season starts again.

Not applicable.

None.