Construction, housing and property
bygganlprod, Production index for construction, new buildings, renovation, building sitesConstruction , Construction, housing and property

Production index for construction


Next update

Key figures

-1.2 %

decrease in the production index for construction in Q1 2021 compared with Q4 2020

Construction, production index. 2015=100
Seasonally adjusted, per centWorking day adjusted, per centIndex
4th quarter 2020 - 1st quarter 20211st quarter 2020 - 1st quarter 20211st quarter 2021
Buildings, total-2.3-1.0112.4
Civil engineering works-0.7-4.2101.3

About the statistics

The production index measures the activity in building and construction industry. The statistics are a volume index and  based on working hours spent in the building or construction site.


Definitions of the main concepts and variables

Employees: Employees mean wage earners and active owners in the enterprise. A distinction is drawn between employees who are actually employed in the construction process and other employees. Contracted out labour, part-time employees, apprentices, holiday temps and others employed for shorter periods are included. Labour hired from employment agencies and enterprises in the construction industry, employees at subcontractors or employees on holiday, on strike, ill or laid off are not included.

Employees actually employed in the construction process : Covers manual workers and site operatives, including working foremen.

Hours worked : Productive hours worked by employees actually employed in the construction.

Indices are published by three types of construction works:

New building : Construction of buildings including site preparation, installation and completion work.

Renovation of building : Improvement, rebuilding, repair and maintenance. Renovation work, which includes addition or extension of a building, is to be classified as new building, if the addition/extension accounts for more than 50 per cent of the value of the project.

Civil engineering work : Transport infrastructure, pipelines, communication and electricity lines, complex constructions on industrial sites and sport recreation construction.

Standard classifications

The index is compiled according to Nace Rev.2. Standard Industrial Classification SIC2007 .

Administrative information

Name and topic

Name: Production index for construction
Topic: Construction, housing and property

Next release

Responsible division

Division for Business Cycle Statistics

Regional level

Index at national level.

Frequency and timeliness

Quarterly frequency. Published within 45 days after the end of the quarter.

International reporting

Transmitted to Eurostat .


Data at the enterprise level are stored as text files on LINUX



Background and purpose

The Production index is a volume index and measures the activity in building and construction industry. Since year 2000 it has been based on  working hours spent in the building- or construction site. Earlier a combination of building area and employment figures were used. The index goes back to 1st quarter 1995 and was first published in 1996.


Users and applications

Users of the statistics include Ministry of Finance, the Central Bank, Statistics Norway's national accounts division, international users and the construction industry.

Equal treatment of users

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on ssb.no at 8 am. Prior to this, a minimum of three months' advance notice is given inthe Statistics Release Calendar.

Principles for equal treatment

Coherence with other statistics

The indices are used directly in the quarterly national account.

The development of the production index is compared with the turnover in the annually structural business statistics or construction turnover.

Legal authority

The Statistics Act 21st of June 2019 number 32, §10 and §20

EEA reference

Council Regulation (EC) No. 1165/98 concerning short-term statistics. Regulation (EC) 1158/2005 of the European Parliament and of the Council amending CR No. 1165/98. Commission Regulation (EC) No. 1503/2006 implementing and amending CR No 1165/98 as regards definition of variables, list of variables and frequency of data compilation. Regulation (EC) 1893/2006 of the European Parliament and of the Council establishing the statistical classification of economic activities NACE Rev.2.



All activity in the construction industry section F except group 41.1 Development of building projects Standard Industrial Classification (SIC2007) . The observation unit was local Kind of Activity Unit (local KAU) until 2016 when the survey changed to collect data from enterprises.


Data sources and sampling

The data for computing the index is obtained from two different sources: the Central Register of Local KAUs and Enterprises and a quarterly survey.

 A sample survey of about 2 000 units. All enterprises with more than 50 employees are included. Sub-samples are selected for enterprises with less than 50 employees, stratified according to detailed industry classification and size in terms of turnover. Enterprises with less than two employees are not included in the survey. About 1/4 of the enterprises with less than 50 employees are rotatied yearly.

This full sampling is new from  the 1st quarter of 2014.  Earlier the limit for full sampling was units with 20 and more employees.

Collection of data, editing and estimations

The data is collected by postal survey at the end of the quarter, and the questionnaire can be filled out by Statistics Norway on Internet Altinn, Altinn.no. 

Controls include checking out the consistency in the values stated on the form, and the correspondence with values given the previous quarter. If a discrepancy is discovered, the respondent is contacted by phone or e-mail.

The production index is based on hours worked on construction sites as an input variable. The construction total index is calculated directly on the basis of total hours worked. The sub indices for building, renovation and civil engineering works are calculated by distributing the hours worked according to the number of persons employed in those types of work, given by the companies. The Quarterly sample data are grossed up to achieve assessments of total hours worked, using the ratio between the number of employees in the population and in the responding units. The series of hours worked are not modified with productivity factor. The index is chained annually upon rotation of the sample.

The production index is published as a volume index with the year 2015 as reference period.

The production index is adjusted for seasonal variations and for working days.

More information about seasonal adjustments .

Seasonal adjustment

What is seasonal adjustment?

Monthly and quarterly time series are often characterised by considerable seasonal variations, which might complicate their interpretation. Such time series are therefore subjected to a process of seasonal adjustment in order to remove the effects of these seasonal fluctuations. Once data have been adjusted for seasonal effects by a seasonal adjustment tool (SAS), a clearer picture of the time series emerges.

For more information on seasonal adjustment:   metadata on methods: seasonal adjustment

Seasonally adjusted series

For the production index, construction 5 seasonally series are published; Total, buildings and civil engineering works.


Not relevant.

Comparability over time and space

From 1995 to 1998 the index for new buildings were calculated from a model based on new buildings started from the building register in the Matrikkel and the rest was based on employment-figures. In 1999 the figures from the Matrikkel was not used because of increasing reporting delay in the register. The calculation method was changed in 2000. From the 1st quarter of 2000, the calculation of the production index is based on measuring the number of hours worked. Earlier, the calculation is based on employment figures. The quarterly figures calculated after 1999 are therefore not directly comparable with the figures calculated before the 1st quarter of 2000.

Before the second quarter of 2004, contracted labour was not included. From the second quarter of 2004 labour hired from employment agencies was included. This was reversed in 2011 as it occurred that the companies omit to include contracted labour in their reports. Therefore, Statistics Norway will use other sources to estimate hours worked in construction industry by labour hired from employment agencies.


Accuracy and reliability

Sources of error and uncertainty

The data processing routines includes comprehensive control systems.

There will be a certain amount of non-response in form-based surveys such as the production index for building and construction. This is because some respondents either do not return their forms (total non-response) or return them incompletely filled out (partial non-response). Response rate at the expiration of the deadline is about 40 per cent. Following reminders it climbs to around 97 per cent. Total non-response is adjusted in the estimation procedure. By partial non-response the companies usually are contacted.

About 5 per cent of the units in the population are included in the sample survey. The sample overall coverage exceeds 55 per cent of the population in terms of employment. Gross margin ratio on subclass level shows some variation. For the 3rd quarter of 2007 a variation coefficient of 0.84 per cent was calculated.


Not relevant.

About seasonal adjustment

General information on seasonal adjustment

What is seasonal adjustment?

Monthly and quarterly time series are often characterised by considerable seasonal variations, which might complicate their interpretation. Such time series are therefore subjected to a process of seasonal adjustment in order to remove the effects of these seasonal fluctuations. Once data have been adjusted for seasonal effects by X-12-ARIMA or some other seasonal adjustment tool, a clearer picture of the time series emerges.

For more information on seasonal adjustment:   metadata on methods: seasonal adjustment

Seasonally adjusted series

For the production index, construction 5 seasonally series are published; Total, buildings and civil engineering works.

Why seasonally adjust these statistics?

The production index is adjusted for seasonal variations since analysis show a stable seasonally pattern. By removing the seasonal effects, the underlying economic development becomes more evident.


Pre-treatment routines/schemes

A detailed pre-tratment is done. This means that the tools are based on special adjusted models and not based on standard options in the seasonal adjustment tools.

Calendar adjustment

Calendar adjustments are performed on all series showing significant and plausible calendar effects within a statistically robust approach, such as regression or RegARIMA (a regression model with an ARIMA structure for the residuals).

Methods for trading/working day adjustment

Working days are not adjusted for, but the figures are adjusted for easter-variations. Still these figures are called and reffered to as working days adjusted figures.

Correction for moving holidays

Correction within proportional number of day adjustment, in which the effect of moving holidays is estimated using the proportion of the different holidays in each month/quarter. This is adjusted for Norwegian holidays.

National and EU/euro area calendars

Depending on use eighter a Norwegian calendar or a European EU/EU-area calendar is used.

Treatment of outliers

Outliers are detected automatically by the seasonal adjustment tool. When they are identifyed and an explanation for their values are found they are included as a regressor in the model.

Model selection

Pre-treatment requires choosing an ARIMA model, as well as deciding whether the data should be log-transformed or not.

Model selection is primarily automatic, but in some cases models are selected manually

Decomposition scheme

The decomposition scheme specifies how the various components – basically trend-cycle, seasonal and irregular – combine to form the original series. The most frequently used decomposition schemes are the multiplicative, additive or log additive.

Manual decomposition scheme selection after graphical inspection of the series.

Seasonal adjustment

Choice of seasonal adjustment approach


Consistency between raw and seasonally adjusted data

Do not apply any constraint.

Consistency between aggregate/definition of seasonally adjusted data

In some series, consistency between seasonally adjusted totals and the original series is imposed. For some series there is also a special relationship between the different series, e.g. GDP which equals production minus intermediate consumption.

Do not apply any constraint.

Direct versus indirect approach

Direct seasonal adjustment is performed if all time series, including aggregates, are seasonally adjusted on an individual basis. Indirect seasonal adjustment is performed if the seasonally adjusted estimate for a time series is derived by combining the estimates for two or more directly adjusted series.

Direct approach where the raw data are aggregated and the aggregates and components are then directly seasonally adjusted using the same approach and software. Any discrepancies across the aggregation structure are not removed.

Horizon for estimating the model and the correction factors

When performing seasonal adjustment of a time series, it is possible to choose the period to be used in estimating the model and the correction factors. Correction factors are the factors used in the pre-treatment and seasonal adjustment of the series.

The whole time series is used to estimate the model and the correction factors.

Audit procedures

General revision policy

Seasonally adjusted data may change due to a revision of the unadjusted (raw) data or the addition of new data. Such changes are called revisions, and there are several ways to deal with the problem of revisions when publishing the seasonally adjusted statistics.

Both raw and seasonally adjusted data are revised between two consecutive official releases of the release calendar.

Comments: Raw data are not revised.

Concurrent versus current adjustment

The model, filters, outliers and regression parameters are re-identified and re-estimated continuously as new or revised data become available.

Horizon for published revisions

The entire time series is revised in the event of a re-estimation of the seasonal factors.

Quality of seasonal adjustment

Evaluation of seasonally adjustment data

Continuous/periodical evaluation using standard measures proposed by different seasonal adjustment tools.

Quality measures for seasonal adjustment

No quality measures for seasonal adjustment assessment are used.

Special cases

Seasonal adjustment of short time series

All series are sufficiently long to perform an optimal seasonal adjustment.

Treatment of problematic series

None of the published series are viewed as problematic.

Posting procedures

Data availability

Raw and seasonally adjusted data are available.

All metadata information associated with an individual time series is available.

Press releases

In addition to raw data, at least one of the following series is released: pre-treated, seasonally adjusted, seasonally plus working day adjusted, trend-cycle series.

Both levels/indices and different forms of growth rates are presented.

For each series, some quality measures of the seasonal adjustment are presented.

Relevant documentation