1. Contact |
1.1 Contact organisation |
Italian National Institute of Statistics |
1.2 Contact organisation unit |
Consumer Price Division |
1.3 Contact name |
1.4 Contact person function |
1.5 Contact mail address |
Via Torino 6, 00184 Roma - ITALY |
1.6 Contact email address |
1.7 Contact phone number |
1.8 Contact fax number |
2. Metadata update |
2.1 Metadata last certified |
17/07/2017 |
2.2 Metadata last posted |
17/07/2017 |
2.3 Metadata last update |
17/07/2017 |
3. Statistical presentation |
3.1 Data description |
The House Price Index (HPI) measures the evolution of market prices of all residential properties that are purchased by households (flats, detached houses, terraced houses, etc.), both new and existing, independently if bought for own-occupancy or as an investment. The price of land is included in prices and weights. The HPI is released quarterly and is composed by the following two sub-indices: - Price index for new dwellings; - Price index for existing dwellings. The HPI compilation follows methodological standards set out in the Technical Manual on Owner-Occupied Housing (OOH) for HICP provided by Eurostat to ensure comparability of HPI indices across Member States. |
3.2 Classification system |
Index number and weights are made available at the level of detail established by the OOH Commission Regulation No 93/2013. In particular the classification system for HPI is the following: H.1. Purchases of dwellings; H.1.1. Purchases of new dwellings; H.1.2. Purchases of existing dwellings. |
3.3 Coverage - sector |
The HPI covers the whole household sector in particular the expenditure on purchases of dwellings carried out by households over the whole national territory. |
3.4 Statistical concepts and definitions |
The HPI covers purchases of new dwellings and existing dwellings. The HPI compilation is based on administrative data; in particular, prices of dwellings are gathered from notarial deeds of sales data provided by Tax Office. The HPI compilation is based on final market prices that are paid by households (VAT included); non-market prices are ruled out from the scope of the HPI (for example, the calculated final price for a dwelling that was developed by a step-by-step self-building is excluded). The HPI are calculated using a chained Laspeyres formula. The reference base year for all indices is 2015=100. |
3.5 Statistical unit |
The statistical unit of the HPI is the household who purchases a residential property. |
3.6 Statistical population |
The target population is the set of households who purchase residential properties, both new and existing, independently for own-occupancy or as an investment. |
3.7 Reference area |
Data are available for the whole national territory, excluding two provinces having a different cadastral system (totalizing about 2.3% of Italian population). |
3.8 Coverage - Time |
Data are available from the third quarter 2007; at the moment indices are published starting from the first quarter of 2010. |
3.9 Base period |
The reference base year is 2010 (2015=100). |
4. Unit of measure |
Following units are used:
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5. Reference Period |
Quarter (indices and rates). |
6. Institutional Mandate |
6.1 Institutional Mandate - legal acts and other agreements |
Commission Regulation (EU) No 93/2013 of 1 February 2013 laying down detailed rules for the implementation of Council Regulation (EC) No 2494/95 concerning harmonised indices of consumer prices, as regards establishing owner-occupied housing price indices. Italian National Statistical Programme 2014–2016, 2015-2016 revision, entered into force with the Decree of the President of the Council of Ministries 24 September 2015. |
6.2 Institutional Mandate - data sharing |
Istat is the unique national Agency responsible for the Italian HPI. |
7. Confidentiality |
7.1 Confidentiality - policy |
Data are published up to the level of detail described in the OOH Regulation. |
7.2 Confidentiality - data treatment |
Not relevant. |
8. Release policy |
8.1 Release calendar |
The dates of HPI release are available on Istat website. |
8.2 Release calendar access |
In December of each year Istat publishes a release calendar giving the precise release dates for the coming year. The calendar is distributed to the press and is available free of charge to interested parties. The calendar is also disseminated on Istat website http://www.istat.it/en/information/journalists. |
8.3 Release policy - user access |
Data are disseminated to all users through Istat website. |
9. Frequency of dissemination |
Indices are disseminated quarterly; weights are disseminated annually. |
10. Accessibility and clarity |
10.1 Dissemination format - News release |
On-line press Release – Consumer Prices (Comunicato Stampa — Prezzi delle abitazioni). |
10.2 Dissemination format - Publications |
Not available. |
10.3 Dissemination format - online database |
Not available. |
10.4 Dissemination format - microdata access |
Micro-data are not disseminated. |
10.5 Dissemination format - other |
Not available. |
10.6 Documentation on methodology |
Methodological note at the page http://www.istat.it/en/archive/163805 on Istat website. |
10.7 Quality management - documentation |
Not available at the moment. |
11. Quality management |
11.1 Quality assurance |
Continuous efforts to strengthen and improve the procedures of data control checks and adjustment for quality changes are carried out according to the guidelines and standard set out in the Technical manual on Owner-occupied housing for HICP. |
11.2 Quality management - assessment |
Istat monitors the quality of data set provided by Tax Office, the production process and carries out dissemination according to guidelines and standards set out in the Technical manual on Owner-Occupied Housing for HICP. |
12. Relevance |
12.1 Relevance - User Needs |
First of all, HPI respond to the needs of Commission which releases the report on the Macroeconomic Imbalance Procedure (MIP); in fact HPI (deflated by consumption deflator - the annual growth rate) is one of MIP indicators. HPI is also used by the Commission for international comparison. Moreover HPI is one of the FSIs (Financial Soundness Indicators) Stability. Finally HPI responds to the needs of users interested in the behaviour of the domestic house price market. |
12.2 Relevance - User Satisfaction |
Not available. |
12.3 Completeness |
All expenditure categories defined in OOH Regulation are covered. |
13. Accuracy |
13.1 Accuracy - overall |
HPI is perceived to be accurate and to reflect the overall behaviour of the housing market in a good manner. |
13.2 Sampling error |
HPI is not subject to sampling error because index calculation is based on administrative data that cover the universe of dwelling transactions (except only two provinces). |
13.3 Non-sampling error |
Not available. |
14. Timeliness and punctuality |
14.1 Timeliness |
Provisional indices are transmitted to Eurostat 85 days after the end of reference period; final ones are transmitted in the following quarter. |
14.2 Punctuality |
Indices are transmitted to Eurostat according to its own calendar. |
15. Coherence and comparability |
15.1 Comparability - geographical |
Data are comparable across NUTS II regions. |
15.2 Comparability - over time |
Data are comparable over time. |
15.3 Coherence - cross domain |
Not applicable. |
15.4 Coherence - internal |
Data are checked for internal consistencies. |
16. Cost and Burden |
Not relevant cost for data collection and no burden for the respondents. A burden is on charge of Tax Office that prepares the data set to be sent to Istat. Production process is carried out by Istat in house and therefore the costs are the costs of the resources dedicated in terms of personnel and IT. |
17. Data revision |
17.1 Data revision - policy |
HPI released each quarter are provisional and they are subject to revision with new information available the following quarter. Final indices relating to the previous quarter are published in the following quarter. |
17.2 Data revision - practice |
Users are informed about revision in the press releases. The text of the press release contains a note explaining which one is a preliminary HPI estimate subject to revision and which one is definitive. |
18. Statistical processing |
18.1 Source data |
HPI compilation is based on administrative data; in particular, prices of dwellings are gathered from notarial deeds of sales data provided by Tax Office. Transaction prices refer to the price paid when the final deed is signed and ownership rights are transferred. Data are sent to Istat by Tax Office on quarterly basis; prices of dwellings are taken into account in the quarter where the final deed of sales is signed. Administrative data provided by Tax Office cover expenditure on purchases of dwellings carried out by households over the whole national territory, excluding two provinces (Trento and Bolzano) that are regulated by a different cadastral system and that represent about 2.3% of Italian population. |
18.2 Frequency of data collection |
Data are collected quarterly. |
18.3 Data collection |
Data are encrypted by Tax Office and transferred to Istat using a secure transfer protocol. |
18.4 Data validation |
Data validation principally consists in outlier detection. This is made:
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18.5 Data compilation |
HPI are calculated using a chained Laspeyres formula. HPI are calculated using stratification combined with hedonic method to take into account of quality changes. For each stratum (defined on the base of territorial variables, demographic variables and dwelling size), the elementary index is a Jevons index adjusted by a quality change index calculated from a vector of regression coefficients obtained by the estimation on a chosen reference set of price observations. Elementary indices are then aggregated to obtain the two sub-indices (new and existing dwellings) and the overall index. The general aggregate index is calculated as a weighted arithmetic average of stratum elementary indices where the weight of its stratum is proportional to its importance on the total expenditure of households to buy houses (weights are updated yearly and are estimated on the basis of the same data base used for processing price information). |
18.6 Adjustment |
For the quality adjustment a mix of data stratification and the hedonic method of re-pricing has been adopted. Re-pricing methods imply the use of a hedonic function to clean prices from the influence of qualitative features and geographical locations. Hedonic function is estimated for each year y, during the indices re-basement, through a regression model that uses the data of the previous year (y-1): estimated regression coefficients are kept constant for the whole reference year (y). A model is estimated for each geographical area (North-west, North-east, Centre, South and Islands) and for new and existing houses separately (in order to guarantee a minimum amount of observations in each stratum, total strata are 240, whereof 192 are referred to the existing ones and 48 to the new ones). In the model, the main explicative variables are the following ones: a) natural logarithms of the surface, b) percentage of the surface of the house appurtenance, c) house typology, d) the floor; the dependent variable is the natural logarithms of the price for square metre. |
19. Comment |
None. |