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.
Index of Production in Construction (IPC) is designed to be an indicator of the economic cycle. In Croatia Index is based on the number of actually worked hours on construction sites. The IPC is broken down into two sub-indices: building construction and civil engineering. Data are collected by using the reporting method on the Monthly and the Quarterly Report on Construction (GRAĐ-21/M and GRAĐ-21/3M forms).
3.2. Classification system
NACE Rev.2. is used. The breakdown of the indicator into building and civil engineering works is based on the Classification of Types of Constructions (CC).
3.3. Coverage - sector
Construction covers economic activities listed in section F of NACE Rev. 2. – Construction (divisions 41, 42 and 43). The breakdown into building and civil engineering works required for certain indicator is based on the Classification of Types of Constructions (CC).
The coverage based on the activity (NACE) classification is a cut off survey on the basis of the number of employees. Included are business entities (legal entities and tradesmen) and parts thereof employing 20 or more persons.
The exclusion of small business entities does not cause a significant bias. If we compare year to year growth rate of hours worked on sites produced by the Annual survey (business entities employing 5 or more persons) and index produced by the Monthly survey (business entities employing 20 or more persons), trend is similar (for example, in 2023 growth rate was 5.1 in the Monthly survey and 7.2 in the Annual survey).
3.4. Statistical concepts and definitions
The objective of the production index is to measure changes in the volume of output at close and regular intervals. It provides a measure of the volume trend in value added over a given reference period.
The volume index of construction is compiled from the number of actually worked hours on construction sites, and covers all types of construction works (new constructions and reconstruction, repair work and maintenance) and all types of constructions (broken down to residential buildings; non-residential buildings; transport infrastructure; pipelines, communication and electricity lines; complex construction of industrial sites; other civil engineering).
Included are hours of work done by employees directly involved in the production process and overtime. Excluded are hours of work in business administration and any paid non-working period (holidays, sick leave, etc.).
Productivity factors are applied to adjust data series of hours worked. The productivity factor is estimated on the annual basis by dividing the deflated value of works done with hours worked, separately for buildings and for civil engineering works. The value of works done are deflated with construction value added from National Accounts. The fluctuation of individual values of the productivity factor is alleviated by using the exponential smoothing of the time series. After the calculation of indices for buildings and for civil engineering works, the next phase includes the calculation of the index for the total construction indirectly by aggregating these two semi-indices applying the Laspeyres’ formula. Weights are defined according to the share of the value added from section F – Construction taking into account the production factors costs from structural business statistics in a base year.
Since the productivity factor is estimated at the annual level on the basis of the data from the previous year, data for the whole reference year is issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results are issued.
The breakdown of production in construction into buildings and civil engineering works is based on the Classification of Types of Constructions (CC).
Detailed definitions of the indicators are described in the Regulation (EU) 2019/2152 of the European Parliament and of the Council, and in the Commission Implementing Regulation (EU) 2020/1197.
Data are collected monthly and include hours worked on construction sites during the reporting month.
3.5. Statistical unit
Statistical unit is kind of activity unit. It coincides with the reporting unit.
3.6. Statistical population
Section F of NACE broken down into building construction and civil engineering works according to the Classification of Types of Constructions (CC).
This survey is based on the non-probability (cut-off) sampling, which means that for business entities with 20 and more employees very exhaustive survey is carried out. For business entities less than 20 employees’ data are not collected and sampling is not applied.
The target population are all active business entities in the Statistical Business Register which are classified in division 41, 42 and 43, and employing 20 or more persons.
3.7. Reference area
The whole territory of the Republic of Croatia - no regions are excluded. The regional coverage has not changed in any way.
3.8. Coverage - Time
Construction production index has been produced using the current method (based on hours worked on construction sites) since 2000 for the main aggregates, for the total, building construction and civil engineering works. Time series are not available before 2000.
3.9. Base period
Base year is 2021
Reference year is 2021
The base year is the same as reference year and this is the year when the index equals 100 (monthly average of the base year = 100).
The same base and reference periods are applied to data released nationally and to those transmitted to Eurostat.
Publication date of the index for period 1q/2024 is chosen for changing the base year.
Indices, percentage changes (%).
Month
6.1. Institutional Mandate - legal acts and other agreements
The legal basis for the Monthly/Quarterly Statistical Survey on Construction (GRAĐ-21/M and GRAĐ-21/3M forms) are:
The Official Statistics Act (OG, No 25/20 and 155/23)
The Annual Implementation Plans of Statistical Activities of the Republic of Croatia
REGULATION (EU) 2019/2152 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 November 2019 on European business statistics, repealing ten legal acts in the field of business statistics
COMMISSION IMPLEMENTING REGULATION (EU) 2020/1197 of 30 July 2020 laying down technical specifications and arrangements pursuant to Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics repealing ten legal acts in the field of business statistics
The Commission Regulation (EC) No 1893/2006 of 20 December 2006 establishing the statistical classification of economic activities NACE Revision 2
Response is obligatory. The obligation on units to submit the report is based on the Article 45 of the Official Statistics Act (OG, No 25/20 and 155/23). In case of the refusal to provide data, the provision of incomplete or incorrect data or the provision of data out of the time schedule, penalty provisions defined in Article 76 of the Act shall apply.
Data are regularly transmitted to Eurostat and to other international institutions (e.g. International Monetary Fund).
7.1. Confidentiality - policy
National legislation:
Terms and conditions, under which official statistics are produced, including confidentiality of individual responses, are governed by the Official Statistic Act (OG, No 25/20 and 155/23). Individual data are strictly confidential and must not be published or reported.
Also, there is the Ordinance on the conditions and terms of access and use of confidential statistical data of the Croatian Bureau of Statistics for scientific purposes (OG, No. 5/23).
Confidentiality and reference to the Official Statistics Act are available on the data collection questionnaires.
European legislation:
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.
7.2. Confidentiality - data treatment
Confidential data are treated according to policy rules (see point 7.1).
Data are published only on the level at which they are not confidential.
8.1. Release calendar
A release schedule for the upcoming year, specifying dates, reference period and level of statistical publication, is published each October in the Calendar of Statistical Data Issues and each December in the CBS Publishing Programme. These documents are available in both Croatian and English.
Statistical publications are released simultaneously to all interested parties at the same time (11:00) by the issuance of the press release, first release - Construction Work Indices.
No users have prior access to the data.
There is no internal government pre-release access to the statistics for construction production indices.
Data on construction production index - production (total - F) are transmitted to Eurostat monthly, beginning with January of 2000 with the required level of detail and timeliness, on a same day when data are published in the national publication (average 54 days after the end of the reference period).
Monthly - both to Eurostat and nationally.
10.1. Dissemination format - News release
Data are published monthly according to release calendar in the First release "Construction work indices", on the CBS website:
News releases are issued at 11 a.m on CBS website. First release contains indices for total construction and two subindices, for buildings and civil engineering works.
Indices of construction works are presented as gross (non-adjusted) indices, seasonally adjusted indices, working-day adjusted indices, trend indices and as various types of growth rates in tabular form. Seasonally adjusted indices are also presented in graphic form.
10.2. Dissemination format - Publications
Not available.
10.3. Dissemination format - online database
Data on production indices are available on the STS Database (the database of short-term statistics) at Reports (dzs.hr)
10.4. Dissemination format - microdata access
The conditions under which certain users can have access to microdata are regulated by The Ordinance on the conditions and terms of access and use of confidential statistical data of the Croatian Bureau of Statistics for scientific purposes (OG, No. 5/23).
Monthly indicators are transmitted to Eurostat using SDMX for total production (F) on a same day when the data are published in the national publication (average 54 days after the end of the reference period).
10.6. Documentation on methodology
European business statistics compilers’ manual for short-term business statistics — 2021 edition.
European business statistics methodological manual for compiling the monthly index of production in construction — 2021 edition.
More detailed notes have been published as methodological guidelines “Monthly and Quarterly Report on Construction (Revision)” (Handbook, No 75/17 of the Croatian Bureau of Statistics), and are available on the CBS website Microsoft Word - MU-75.doc (dzs.hr).
All results are displayed exclusively in the form of indices. The monthly index of production in construction (2021=100) is published for total construction and for buildings and civil engineering works.
Indices of construction works are presented as gross (non-adjusted) indices, seasonally adjusted indices, working-day adjusted indices, trend indices and as various types of growth rates in tabular form. Seasonally adjusted indices are also presented in graphic form.
10.7. Quality management - documentation
Following the example of the European Statistical System, the Croatian Bureau of Statistics has developed a model of the Total Quality Management based on the Code of Practice of European Statistics. It is the model that is fully adjusted to the statistical purposes.
Quality checks and validation of data are done throughout the whole process. To ensure the quality of results, CBS develops, produces and disseminates data based on the same standards and harmonized methods. In this respect, CBS applies the criteria of relevance, accuracy, timeliness, accessibility and clarity, comparability according to the Official Statistic Act (OG, No 25/20 and 155/23).
11.2. Quality management - assessment
The quality of the data corresponds with requirements of relevance, accuracy, timeliness and punctuality and comparability. The index of production in construction is an important indicator used both nationally and by the EU. All users’ needs are fulfilled. Coverage of the indices is the whole Croatian territory. Indices are produced at 1-digit level of CC (for buildings, civil engineering works and total). Indices are based on reliable data. Publications of result are almost punctual. Before results are presented to users, additional quality control of statistical data is performed and data are compared with previous and corresponding period and checks with different source are made. All data have been available since January 2000 and are comparable and free of any break in series.
Following the example of the European Statistical System, the Croatian Bureau of Statistics has developed a model of the Total Quality Management based on the Code of Practice of European Statistics. It is the model that is fully adjusted to the statistical purposes.
12.1. Relevance - User Needs
The user’s needs are fulfilled. The indices are used by different users, both national and EU ones. The index of production in construction has an essential role in the calculation of GDP. Users of statistical data on construction production indices can be found in all areas of economic and social life, beginning with individual citizens, business entities, media, economic analysts, researches and students, to state government bodies, professional business organisations (the Croatian Chamber of Economy), non-profit organisations (the Croatian Chamber of Trades and Crafts, the Croatian Employers' Association), financial institutions (the Croatian National Bank, Raiffeisen bank, etc.), as well as Eurostat and internal users in CBS (national accounts).
12.2. Relevance - User Satisfaction
Not available.
12.3. Completeness
The international and national requirements of time series are fulfilled.
Indices at 1-digit level of CC (for buildings, civil engineering works and total) are available on a monthly basis from January 2000.
It is in accordance with the requirements of Regulation No 2019/2152 and Regulation No 2020/1197.
13.1. Accuracy - overall
The comprehensive survey is performed on a cut-off census (included are business entities and parts thereof employing 20 or more persons). Data are not collected, nor the sampling procedure is done for business entities with less than 20 employees.
The exclusion of small business entities does not cause a significant bias. If we compare year to year growth rate of hours worked on sites produced by the Annual survey (business entities employing 5 or more persons) and index produced by the Monthly survey (business entities employing 20 or more persons), trend is similar (for example, in 2023 growth rate was 5.1 in the Monthly survey and 7.2 in the Annual survey).
There was a significant deviation betwen the provisional and the final results in 2024. (mean revision for 2024=1,5) due to the revision of deflator based on construction value added from National accounts.
Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
13.2. Sampling error
Not relevant. Quantifying sampling errors is not possible because the sample is not based on random sampling. The comprehensive survey is performed on a cut-off census (included are business entities and parts thereof employing 20 or more persons). For business entities less than 20 employees' data are not collected and sampling procedure is not applied.
It is not possible to evaluate the accuracy of the change in the occurrence in the selected model due to the non-existence of a secondary data source for the whole set. We can evaluate only the accuracy of the trend of the change in the occurrence at the monthly and annual level. The evaluation for the non-sampled part of the population (business entities employing less than 20 persons) is not carried out due to the specific character of the construction activity (the major number of small business entities executes all works irrespective of the registered activity). Therefore, it is impossible to distinguish, on the basis of the registered activity, how many working hours these business entities did on buildings and how many on civil engineering works. Rates calculated according to data obtained from the Fina's Annual Report for 2023 show that business entities employing less than 20 persons, participate in total turnover with 31.8%.
The reasons why sampling isn't applied are large number of small units which should be included in the sample, huge respondent burden and huge cost of data gathering for the CBS.
The exclusion of small business entities does not cause a significant bias. If we compare year to year growth rate of hours worked on sites produced by the Annual survey (business entities employing 5 or more persons) and index produced by the Monthly survey (business entities employing 20 or more persons), trend is similar (for example, in 2023 growth rate was 5.1 in the Monthly survey and 7.2 in the Annual survey).
13.3. Non-sampling error
Unit non response
The survey is compulsory. Response rate is 98.2%. All data are available according to deadlines. For late or missing data, units are contacted by phone or mail and asked to provide the missing data. If units are not available, credible estimates are used to compensate for the late or missing data (approx. 1.8% of all observed units).
Weighted unit response rate is 98.0%. Weighting variable is value of works done with own workers.
Item non-response rates
No case of item non-response is involved in the survey, since during data editing phase, units which did not fully complete the questionnaire are contacted by phone or e-mail and asked to provide the missing data. Every month item response rate of 100% is achieved.
The undercoverage is mainly caused by misclassification of the business entity in the Statistical Business Register – SPR (e.g., registering an activity different from construction although the business entity is engaged in construction works). There is no register on the number of non-covered reporting units due to the misclassification. Since the comparison of the SPR data with another data source (it does not exist) was not possible at the time when the contingent of reporting units was formed, estimates for them cannot be made because their significance is unknown. Consequently, the target population in this survey is limited to the one covered by the frame, while the influence of non-covered ones is neglected. Nevertheless, great efforts are done in the Croatian Bureau of Statistics to minimise this error. Specifically, while collecting, controlling reports and contacting reporting units for incorrect and doubtful reports and perceiving that the activity of an reporting unit included in their coverage was misclassified, experts in various Units submit information on that to the Statistical Business Register Unit. This Unit regularly updates its data base and therefore it may be expected that such misclassifications will be gradually cut down in the Statistical Business Register.
Overcoverage: As it is the case with the undercoverage, this error is mainly caused by misclassification of an activity in the SPR (a business entity has been classified in the construction activity, while in fact it is engaged in an activity other than construction). This kind of error is regularly disclosed during the process of collecting and controlling the data as well as while contacting reporting units. There were 5 reporting units in 2024 included in the coverage that were in fact engaged in an activity other than construction, which made 0.4% of all units included in the coverage. The major part of those units was engaged in the industrial or trade activity. The obtained information was submitted to the Statistical Business Register Unit for data updating.
Double classification: A risk/probability for this error is zero, since the coverage is formed on the basis of SPR. To date, multiple coverage of reporting units has not been recorded.
Measurement errors: Although an alternative data source (that is, data bases/registers to compare data obtained on the Monthly/Quarterly Report on Construction in order to define measurement errors) does not exist, the Construction Statistics Unit compares the trend in volume indices of construction works (which is deduced from hours actually worked) with data on the trend in the number of persons in employment in construction compiled in the Labour Force Statistics Unit. Still, at this comparison one should take into account the difference in methodologies of data collection. According to the methodology applied in the Labour Force Statistics Unit, persons are considered employed as long as their employment record card is kept by the business entity, irrespective of whether they actually work and get paid or not, while the volume index in construction is based on hours actually worked on sites. This is why, in case of economic turmoil, the total number of persons in employment in the construction activity tends to fall at a slower pace than the construction production indices.
Causes of errors in measurements when collecting data that occur due to ignorance, negligence, conscious/unconscious presentation of inaccurate data by respondents due to unclear questions in the questionnaire, measurement units or instructions for filling in the forms are minor due to the fact that the availability of data was taken into consideration while defining their contents. In addition, reporting units are welcome to contact Branch Units of the Croatian Bureau of Statistics (who helps reporting units in filling in reports and controls the completeness and accuracy of data before they are submitted to the Croatian Bureau of Statistics) or directly the Croatian Bureau of Statistics in case they need information or help in resolving ambiguities.
These measurement errors do not represent a major issue, since they are revealed during the visual and calculation control of data before they are entered in the computer as well as by the default computerised logical and calculation control during data processing. When such illogicalities or errors are spotted, reporting units are contacted for the check-up of inaccurate and incomplete data and for the correction of inaccurate data.
14.1. Timeliness
The provisional monthly indicators are transmitted to Eurostat using SDMX for total production on a same day when the data are published in the national publication (average 54 days after the end of the reference period).
Since the productivity factor is estimated at the annual level on the basis of data from the previous year, data for the whole reference year are issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results will be issued. Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
Electronic questionnaires are sent every month to the reporting units. The deadline for replies is the 20th day in a month at the latest, for the previous month. The data collection is completed approximately 15 days after the deadline for replies.
14.2. Punctuality
All new releases are published as announced in the release calendar:
There is no time lag between the delivery dates announced in the calendar and the time the target data are actually delivered.
15.1. Comparability - geographical
Comparability of the methodology used in observing the activity, observation period, dates and modes of data publication for EU Member States are provided in the REGULATION (EU) 2019/2152 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 November 2019 on European business statistics, repealing ten legal acts in the field of business statistics and in the COMMISSION IMPLEMENTING REGULATION (EU) 2020/1197 of 30 July 2020 laying down technical specifications and arrangements pursuant to Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics repealing ten legal acts in the field of business statistics.
This ensures a good comparability of national data.
15.2. Comparability - over time
All data have been available since 2000 and are comparable and free of any break in series.
15.3. Coherence - cross domain
Comparisons are made on “ad hoc” basis and are not published.
Confrontation is made with other available data within CBS (value added from National accounts – section F (construction), number of persons employed in construction from Employment), as well as with monthly/quarterly data published in Eurostat's publications.
Results are:
a) the correlation coefficient of the quarterly growth rates of the IPC and of the value added of the Section F from QNA was computed for the period 2001Q1-2024Q4. Multiple R for this period is 0.82 for calendar-adjusted series and 0.72 for seasonally adjusted series.
b) despite the differences in the methodology (see point 13.3 – measurement errors), when comparing annually data between hours worked (GRAĐ-21/M and GRAĐ-21/3M forms) and total number of persons employed in construction (data from Employment statistics unit), we can conclude that there is a strong correlation between these two variables. Multiple R for the period from 2001 to 2024 is 0.85.
15.4. Coherence - internal
Data are internal coherent.
In 2024:
Burden of respondents: 4370 hours annually for all reporting units.
Total costs of NSI: 6 900 hours annually
17.1. Data revision - policy
The users of statistical data are informed about revisions (preliminary, final data) on the CBS website.
Correction of errors, major changes in the classifications, methodology, base year changes and changes of seasonally adjusted data is possible. Notice about minor changes is given at the time the change is introduced.
The same revision policy is applied to data released nationally and transmitted to Eurostat.
The data publishing revision policy in the Croatian Bureau of Statistics includes the following:
Updating of the Calendar of Statistical Data Issues
Publishing of corrigenda of the published data
1) Updating of the Calendar of Statistical Data Issues
The data publishing revision policy of the Croatian Bureau of Statistics, which is carried out according to the defined deadlines, is carried out by updating the Calendar of Statistical Data Issues. According to the Official Statistics Act, changes in the publishing deadlines for publications/data are announced in advance. The Croatian Bureau of Statistics is obliged to announce each change in the publishing deadlines (the Calendar update) at least three days prior to the date originally announced in the Calendar at the web site of the Croatian Bureau of Statistics.
The update of the publishing deadlines for data or publications (the update of the Calendar) is announced without delay on the Croatian Bureau of Statistics’ website by updating the date in the Calendar and putting the notice beside the Calendar, which says: updated: (the accurate new date).
Therefore, the Calendar that contains the original publishing deadline for a particular publication/statistical information is replaced with the new Calendar which includes the updated publishing deadline. The original Calendar is kept in the Publishing Department which registers every change in publishing deadlines for publications in the Calendar Update Base.
2) Publishing of the corrigenda of the published data
In cases when an error is observed in the published data, the Croatian Bureau of Statistics announces the correction as soon as possible and as simple as possible in order to help the users to clearly see what was changed in comparison to the originally published data. The correction is carried out by marking the incorrect data with an asterisk and creating the corrigendum.
There is an internal vintage database where data on non-adjusted data are stocked. But, a vintage database with all published data on all revisions of calendar adjusted indices, seasonally adjusted indices and trend indices as well as an audit trail of all revisions going back since 2000, is not available.
No special revision calendar exists.
Benchmarking (confrontation) with other statistics is carried out but not published.
Regular revision analyses for the national data sent to Eurostat are not carried out.
17.2. Data revision - practice
The general practice is that all changes in methodology are explained when data based on the new methodology are published for the first time.
Major revisions
Major revisions in the methodology, base year changes, are announced in the First release at the time the change is introduced. These revisions are carried on backwards, since 2000, on monthly basis, for the main aggregates: the total, building construction and civil engineering works. The users of statistical data are informed about major revisions on the CBS website.
No special revision calendar exists.
Impact of major revision has not been analysed yet. Major revisions do not cause time series breaks.
Routine revisions
Since the productivity factor is estimated at the annual level on the basis of data from the previous year, data for the whole reference year are issued as provisional results. When the calculation of the actual productivity for 2024 is done, final results are published together with a change of base and reference year.
Calendar of Statistical Data Issues contains information about the type of data (provisional/final) about to be published in First releases in advance (for the upcoming months).
Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
Quality indicators for the period 2022M1-2024M12:
Gross (non-adjusted) growth rates
1) MAR = 0.4587
2) MR = -0.3915
Working-day adjusted growth rates
1) MAR = 0.5311
2) MR = -0.3287
Routine revisions, related to replacing estimated data with the subsequently reported data, are not carried out, because all data are available according to the deadlines.
There are no routine revisions aiming at acheiving temporal consistency.
If error occurs, corrected data are published in the next issue of First release. Data changed in relation to the first released are disseminated with a comment.
Gross indices and data revised due to the process of Seasonally or Working day adjustment are published each month and are available for the period from January 2000 in the STS Database (the database of short-term statistics) at Reports (dzs.hr).
Working day adjusted and seasonally adjusted time series are revised three times a year (there is an internal vintage database where data on working day adjusted and seasonally adjusted data are stocked, but a vintage database with all previously published seasonally adjusted data is not available).
Size of these revisions has not been calculated yet.
Use of benchmarking and domain (indicator) specific characteristics of revisions are not available.
18.1. Source data
Statistical survey
The Address Book for the monthly survey maintained by the CBS Construction Statistics Unit, derived from the Statistical Business Register.
This survey is based on the non-probability (cut-off) sampling, which means that for business entities with 20 and more employees very exhaustive survey is carried out. For business entities with less than 20 employees’ data are not collected and sampling is not applied.
18.2. Frequency of data collection
Data are collected monthly.
18.3. Data collection
Data are collected by using the reporting method. Two types of questionnaires are used: The Monthly and the Quarterly Report on construction (GRAĐ-21/M and GRAĐ-21/3M forms). The Monthly Report on Construction is collected for each month, except for March, June, September and December. The data for these months are collected on the Quarterly Report on Construction.
Electronic questionnaires are used for gathering data from business in the survey: the Monthly and the Quarterly Report on construction (GRAĐ-21/M i GRAĐ-21/3M forms).
Actions taken to speed up or increase the rate of response: e-mail and phone contacts.
18.4. Data validation
Electronic questionnaires are automatically checked during the data entry by reporting units with a set of warnings and errors, and in the CBS the data entry is again checked by automated error-checking procedures in the branch statistics of the CBS, on micro and macro level.
Reports that fail to meet the quality standard are subject to verification and are corrected as required.
Treatment on micro-data level
Collected data are first checked and verified by staff from the Construction Statistics Unit and then during the automated process of data entering. Quality checking is carried out by using a set of strict manual and electronic logical/calculation controls. Respondents’, coding and data entry errors and inconsistencies are detected and corrected using manual and electronic logical/calculation quality control while editing. Reports that fail to meet the quality standards are subject to verification and are corrected as required. We organised correction procedures by priority: severe errors are generally corrected manually and more effort is spent on these, while minor errors require less attention and are mostly corrected automatically by computer.
Treatment on macro-data level
The macro data tables are verified by experts in construction unit. Data from the actual reporting period is compared with the previous and the corresponding reporting period of the previous year. Furthermore the indices are crosschecked with the number of person employed of the same NACE Rev.2 category. If inconsistencies are detected the data must be verified at micro level again by using raw data of the questionnaries and possibly changed.
Apart from previously mentioned checks done for the purpose of national statistics, neither additional checks are done nor additional tools are used before data are transmitted to Eurostat.
18.5. Data compilation
Data are collected on the base of cut-off survey (census for business entities employing 20 and more persons), without a random sample of business entities with less than 20 persons employed and without an estimate for smaller units.
There are no unit non-response rates and item non-response rates, because reporting units that did not send filled-in questionnaires or did not fully complete the questionnaire are contacted by phone or e-mail and asked to send the filled-in questionnaire for the current month or to provide the missing data.
Index of Production in Construction (IPC) is based on the number of hours worked on sites adjusted with a productivity factor. The productivity factor is estimated on the annual basis by dividing the deflated value of works done with hours worked, separately for buildings and for civil engineering works. The value of works done is deflated with construction value added from National Accounts. The fluctuation of individual values of the productivity factor is alleviated by using the exponential smoothing of the time series. After the calculation of indices for buildings and for civil engineering works, the next phase includes the calculation of the index for the total construction indirectly by aggregating these two semi-indices applying the Laspeyres’ formula. Weights are defined according to the share of the value added at factor costs from section F – Construction, from structural business statistics in the base year.
Since the productivity factor is estimated at the annual level on the basis of data from the previous year, data for the whole reference year are issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results will be issued. Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
18.6. Adjustment
IPC are compiled as unadjusted, WDA, SA and trend-cycle indices.
Seasonal and working-day adjustment has been done by applying the programme interface JDemetra+ (version 2.2.4) by using the X13 ARIMA method on monthly index series (Ø2021 = 100), which starts with January 2000 index. The effect of a random component in the seasonal adjustment process of time series of indices has been excluded.
The calculated series of volume indices of construction works are comparable to those published by the Eurostat.
The average index value of the base year (reference year) is not 100 for the calendar adjusted series and for the calendar and seasonally adjusted series due to the fact that IPC is seasonally adjusted directly without imposing any constraints on seasonally adjusted series.
The model/filter selection - manual.
Parameters re-estimation - ref. periods January, May and September (in other months application of forecasted factors). Annual revision of models, filters, calendar regressors for ref. period January.
Seasonally adjusted time series are revised in January, May and September (all values backwards).
Model used:
(1,1,0) (1,1,1)
(0,1,1) (0,1,1)
(0,1,1) (0,1,1)
Critical value for outlier detection – 4.
Seasonal filters are fixed during the year (revised at the end of a year if necessary):
Total construction (F) - 3x3 seasonal filter
Buildings (CC_1) - 3x5 seasonal filter
Civil engineering (CC_2) - 3x5 seasonal filter
The date of seasonal breaks in the series - 31 December 2005
Direct adjustment (via components) is used.
Checking residual seasonality - qs test and f-test on residual seasonality are checked for every series.
There is no consistency amongst the different levels of breakdown.
Index of Production in Construction (IPC) is designed to be an indicator of the economic cycle. In Croatia Index is based on the number of actually worked hours on construction sites. The IPC is broken down into two sub-indices: building construction and civil engineering. Data are collected by using the reporting method on the Monthly and the Quarterly Report on Construction (GRAĐ-21/M and GRAĐ-21/3M forms).
23 April 2025
The objective of the production index is to measure changes in the volume of output at close and regular intervals. It provides a measure of the volume trend in value added over a given reference period.
The volume index of construction is compiled from the number of actually worked hours on construction sites, and covers all types of construction works (new constructions and reconstruction, repair work and maintenance) and all types of constructions (broken down to residential buildings; non-residential buildings; transport infrastructure; pipelines, communication and electricity lines; complex construction of industrial sites; other civil engineering).
Included are hours of work done by employees directly involved in the production process and overtime. Excluded are hours of work in business administration and any paid non-working period (holidays, sick leave, etc.).
Productivity factors are applied to adjust data series of hours worked. The productivity factor is estimated on the annual basis by dividing the deflated value of works done with hours worked, separately for buildings and for civil engineering works. The value of works done are deflated with construction value added from National Accounts. The fluctuation of individual values of the productivity factor is alleviated by using the exponential smoothing of the time series. After the calculation of indices for buildings and for civil engineering works, the next phase includes the calculation of the index for the total construction indirectly by aggregating these two semi-indices applying the Laspeyres’ formula. Weights are defined according to the share of the value added from section F – Construction taking into account the production factors costs from structural business statistics in a base year.
Since the productivity factor is estimated at the annual level on the basis of the data from the previous year, data for the whole reference year is issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results are issued.
The breakdown of production in construction into buildings and civil engineering works is based on the Classification of Types of Constructions (CC).
Detailed definitions of the indicators are described in the Regulation (EU) 2019/2152 of the European Parliament and of the Council, and in the Commission Implementing Regulation (EU) 2020/1197.
Data are collected monthly and include hours worked on construction sites during the reporting month.
Statistical unit is kind of activity unit. It coincides with the reporting unit.
Section F of NACE broken down into building construction and civil engineering works according to the Classification of Types of Constructions (CC).
This survey is based on the non-probability (cut-off) sampling, which means that for business entities with 20 and more employees very exhaustive survey is carried out. For business entities less than 20 employees’ data are not collected and sampling is not applied.
The target population are all active business entities in the Statistical Business Register which are classified in division 41, 42 and 43, and employing 20 or more persons.
The whole territory of the Republic of Croatia - no regions are excluded. The regional coverage has not changed in any way.
Month
The comprehensive survey is performed on a cut-off census (included are business entities and parts thereof employing 20 or more persons). Data are not collected, nor the sampling procedure is done for business entities with less than 20 employees.
The exclusion of small business entities does not cause a significant bias. If we compare year to year growth rate of hours worked on sites produced by the Annual survey (business entities employing 5 or more persons) and index produced by the Monthly survey (business entities employing 20 or more persons), trend is similar (for example, in 2023 growth rate was 5.1 in the Monthly survey and 7.2 in the Annual survey).
There was a significant deviation betwen the provisional and the final results in 2024. (mean revision for 2024=1,5) due to the revision of deflator based on construction value added from National accounts.
Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
Indices, percentage changes (%).
Data are collected on the base of cut-off survey (census for business entities employing 20 and more persons), without a random sample of business entities with less than 20 persons employed and without an estimate for smaller units.
There are no unit non-response rates and item non-response rates, because reporting units that did not send filled-in questionnaires or did not fully complete the questionnaire are contacted by phone or e-mail and asked to send the filled-in questionnaire for the current month or to provide the missing data.
Index of Production in Construction (IPC) is based on the number of hours worked on sites adjusted with a productivity factor. The productivity factor is estimated on the annual basis by dividing the deflated value of works done with hours worked, separately for buildings and for civil engineering works. The value of works done is deflated with construction value added from National Accounts. The fluctuation of individual values of the productivity factor is alleviated by using the exponential smoothing of the time series. After the calculation of indices for buildings and for civil engineering works, the next phase includes the calculation of the index for the total construction indirectly by aggregating these two semi-indices applying the Laspeyres’ formula. Weights are defined according to the share of the value added at factor costs from section F – Construction, from structural business statistics in the base year.
Since the productivity factor is estimated at the annual level on the basis of data from the previous year, data for the whole reference year are issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results will be issued. Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
Statistical survey
The Address Book for the monthly survey maintained by the CBS Construction Statistics Unit, derived from the Statistical Business Register.
This survey is based on the non-probability (cut-off) sampling, which means that for business entities with 20 and more employees very exhaustive survey is carried out. For business entities with less than 20 employees’ data are not collected and sampling is not applied.
Monthly - both to Eurostat and nationally.
The provisional monthly indicators are transmitted to Eurostat using SDMX for total production on a same day when the data are published in the national publication (average 54 days after the end of the reference period).
Since the productivity factor is estimated at the annual level on the basis of data from the previous year, data for the whole reference year are issued as provisional results. When the calculation of the actual productivity for the reference year is done, final results will be issued. Final results for 2024 are published together with the provisional results for January 2025 (3 months after the end of the reporting year).
Electronic questionnaires are sent every month to the reporting units. The deadline for replies is the 20th day in a month at the latest, for the previous month. The data collection is completed approximately 15 days after the deadline for replies.
Comparability of the methodology used in observing the activity, observation period, dates and modes of data publication for EU Member States are provided in the REGULATION (EU) 2019/2152 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 November 2019 on European business statistics, repealing ten legal acts in the field of business statistics and in the COMMISSION IMPLEMENTING REGULATION (EU) 2020/1197 of 30 July 2020 laying down technical specifications and arrangements pursuant to Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics repealing ten legal acts in the field of business statistics.
This ensures a good comparability of national data.
All data have been available since 2000 and are comparable and free of any break in series.
