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Documentation of statistics Cost index of civil engineering works

23.6.2022 valid documentation

Basic data of the statistics

Data description

The cost index of civil engineering works describes changes in the costs incurred by civil engineering entrepreneurs from the purchase and use of inputs in different civil engineering works. Point figures are produced from the cost index of civil engineering works by sub index and by input group.

More detailed index point figures by cost items are also produced for the entire civil engineering industry. In addition, special M, K, S and H indices are available for use in civil engineering contract agreements.

The indices for civil engineering have been revised and at the same time the base year has been changed at times. The base years of the indices have been the years 1963, 1972, 1980, 1985, 1990, 1995, 2000, 2005 and 2010. Due to difficulties related to the acquisition of data, the cost indices for road and civil engineering works in the base years 1963, 1972, 1980 and 1985 were calculated mainly on the basis of the cost structure and input data of the Roads and Waterways Construction Administration. Thus, the old indices mainly depicted the price development of inputs used by the National Board of Public Roads in their own work and the index of machine work depicted development in the rental prices of machinery.

 

Statistical presentation

The cost index of civil engineering works describes changes in costs incurred by civil engineering entrepreneurs from purchase and use of inputs. Point figures are produced from the cost index of civil engineering works by sub-index and by input group. The data are collected from various sources and published monthly.

Statistical population

The population of the cost index of civil engineering works comprises all production factors used in civil engineering works. 

Statistical unit

The statistical unit of the cost index of civil engineering works is a cost that must be paid by the contractor. A typical reporting unit from which data are collected is such as different enterprises selling materials or services to the contractor.

Unit of measure

The data of the cost index of civil engineering works are released as index point figures. In addition, change percentages calculated based on the indices are also published. The base period is denoted by the number 100.

Base period

The base year of the index currently used is 2015=100. The indices for the years 2010=100 and 2015=100 are structurally comparable. The base years of the indices have been the years 1963, 1972, 1980, 1985, 1990, 1995, 2000, 2005 and 2010.

Due to difficulties related to the acquisition of data, the cost indices for road and civil engineering works in the base years 1963, 1972, 1980 and 1985 were calculated mainly on the basis of the cost structure and input data of the Roads and Waterways Construction Administration. Thus, the old indices mainly depicted the price development of inputs used by the National Board of Public Roads in their own work and the index of machine work depicted development in the rental prices of machinery.

 

Reference period

The index is updated monthly on the 23rd day of the month following the statistical reference month or on the following weekday. The price level of each month is compared with the price level of the base period. The annual index is published in connection with the release of the last month of the year.

Reference area

The geographical reference area of the index of civil engineering works is the whole of Finland.

Sector coverage

The cost index of civil engineering works covers the most typical civil engineering works, which are foundation structures, earth structures, rock structures, surfacing, municipal engineering systems, concrete structures and other technical systems. Indices are calculated for each work category by cost factor, which are labour force, own machinery, purchased machinery services, purchased transport services, materials and overhead site costs. The index is also calculated for crushing work, road maintenance, street maintenance and track maintenance.

Time coverage

The length of the time series of the index varies depending on when the production of the index for the base year was started. Most of the time series start from 1990. The structure of the sub-indices has changed over time and they are not fully comparable for the whole time period.

Frequency of dissemination

The statistics are published monthly on Statistics Finland’s web pages. The cost index of civil engineering works is not revised.

Concepts

Base index

In the base index the price of the calculation period is always compared with the base period. In the base index weights are usually changed less often than yearly, for example, at intervals of five years.

Chain index

In the chain index the comparison takes place always between successive calculation periods. In the chain index the change in two calculation periods is used to take forward the index point figure of the desired base period. In the chain index the weights are changed in principle in each calculation period.

At times the chain index is also mentioned in such cases where the comparison period is retained fixed in comparisons within the year, but the comparison period and the weight structure of the index is changed whenever the year changes.

Cost index

The cost index describes cost changes caused to entrepreneurs from acquisition of inputs for a contract or an assignment.

Costs are accrued by own labour input and various products and services bought. Cost indices are sometimes also referred to as input indices.

The cost index describes changes in prices of cost factors relative to the selected base year. Cost indices are calculated with a method where different cost factors are weighted together by their proportions of total costs. The Laspeyres calculation index formula is used in the calculation, whereby the weights are from the base year.

Statistics Finland produces cost indices for building construction and civil engineering, earth movers and forest machinery, rail, taxi and ambulance transport.

Index

An index is a ratio describing the relative change in a variable (e.g. price, volume or value) compared to a certain base period (e.g. one year). The index point figure for each point in time tells what percentage the given examined variable is of its respective value or volume at the base point in time. The mean of the index point figures for the base period is 100.

Index formula

Index formula is a mathematical function by means of which an individual key figure describing change is calculated from observation values (e.g. Fischer, Laspeyres and Paasche index formulas).

Monthly change

Monthly change is the relative change in the index from a time period one month earlier. The change is usually expressed as a percentage.

Point figure

Point figure is a change quantity used in price indices, which expresses the price, average price or index of the comparison period relative to the price, average price or index of the base period. The point figure of the base period is usually denoted by the number hundred. For example, if the point figure for a commodity at a certain point in time is 105.3, it means that the price of that commodity has risen by 5.3 per cent from the base period.

Weight structure

Describes what meaning each sub-index (commodity, employee group, etc.) belonging to the index has for total index.

Accuracy, reliability and timeliness

Overall accuracy

There are several possible sources of bias in the cost index for civil engineering works. These sources of bias include:
sampling error
deficient product and enterprise frames
non-response
quality changes in products included in the price collection and insufficient consideration of these in the compilation of the index
substitution bias

 

Timeliness

The cost index for civil engineering works is published on the 23rd day of the month following the statistical reference month.

Punctuality

The data are published on the days indicated in the release calendar.

Data revision - practice

Cost index of civil engineering works is not revised.

Comparability

Comparability - geographical

An index that corresponds fully with the cost index of civil engineering works is not published in other countries. Statistics Sweden publishes, for example, an index of street lighting.

Comparability - over time

The sub-indices of the cost index of civil engineering works have changed over time. Since 2005 the sub-indices have remained unchanged.

The indices for civil engineering have been revised and at the same time the base year has been changed at times. The base years of the indices have been the years 1963, 1972, 1980, 1985, 1990, 1995, 2000, 2005 and 2010. Due to difficulties related to the acquisition of data, the cost indices for road and civil engineering works in the base years 1963, 1972, 1980 and 1985 were calculated mainly on the basis of the cost structure and input data of the Roads and Waterways Construction Administration. Thus, the old indices mainly depicted the price development of inputs used by the National Board of Public Roads in their own work and the index of machine work depicted development in the rental prices of machinery.

The cost indices for civil engineering have been revised and at the same time the base year has been changed at times. The currently used classifications of the cost index of civil engineering works have remained unchanged since the base year 2010=100.

Coherence - cross domain

The same base year is used in the statistics as in the other cost indices and the aim is to revise the weight structure of the index within the same schedule as the other cost indices.

Coherence - sub-annual and annual statistics

Annual level indices can be calculated from the monthly level indices of the cost index of civil engineering works.

Coherence -national accounts

National accounts use the cost index of civil engineering works as one deflator in their calculations.

Coherence - internal

The weight structure and sub-indices of the cost index of civil engineering works have changed for different base years. The same classification has been used in the current index 2015=100 as in the index 2010=100. The indices of older base years differ structurally.

Source data and data collections

Source data

The calculation of the cost index of civil engineering works is based on own collection of price data. Other indices, such as the Consumer Price Index, the Producer Price Index for Manufactured Products, the building cost index and so on are also used in calculating the index.

Data collection

A web questionnaire is used in the data collection. A reminder is sent to the respondents by email when the data collection has been opened.

To some of the respondents an email questionnaire is sent, or price data are inquired by telephone. Some of the price data are collected directly from web pages or other indices are utilised.

 

Frequency of data collection

The data for the cost index of civil engineering works are mainly collected monthly or less frequently.

Methods

Data compilation

As a rule, the previous price is used when price data are missing. Imputation is not used much in the calculation of the index of civil engineering works because the aim is to include all price observations in the calculation. Imputation is not used in the index due to the low number of price observations.

The checked observations form the statistical data. Price observations temporarily missing are imputed with price changes of other corresponding products or the price of the previous month is used. An operator of the same size category is selected as the new data provider for permanently missing price observations.

Index point figures are calculated with the base strategy utilising Laspeyres’ index formula. The observations are aggregated with weighting coefficients for products and data providers to the higher product group levels and finally into an overall index.
The weight coefficients are used to estimate index point figures and price changes describing the population.

 

Data validation

Changes of over 10 per cent are automatically taken into account in the calculation of the index and also if prices have not changed in a year.

Missing price data are also taken into account.

 

Principles and outlines

Contact organisation

Statistics Finland

Contact organisation unit

Social Statistics

Legal acts and other agreements

The compilation of statistics is guided by the Statistics Act. The Statistics Act contains provisions on collection of data, processing of data and the obligation to provide data. Besides the Statistics Act, the Data Protection Act and the Act on the Openness of Government Activities are applied to processing of data when producing statistics. 

Statistics Finland compiles statistics in line with the EU’s regulations applicable to statistics, which steer the statistical agencies of all EU Member States.  

Further information: Statistical legislation 

Confidentiality - policy

The data protection of data collected for statistical purposes is guaranteed in accordance with the requirements of the Statistics Act (280/2004), the Act on the Openness of Government Activities (621/1999), the EU's General Data Protection Regulation (EU) 2016/679 and the Data Protection Act (1050/2018). The data materials are protected at all stages of processing with the necessary physical and technical solutions. Statistics Finland has compiled detailed directions and instructions for confidential processing of the data. Employees have access only to the data essential for their duties. The premises where unit-level data are processed are not accessible to outsiders. Members of the personnel have signed a pledge of secrecy upon entering the service. Violation of data protection is punishable. 

Further information: Data protection | Statistics Finland (stat.fi) 
 

Confidentiality - data treatment

Price and enterprise data are processed so that data on an individual enterprise cannot be identified.

Release policy

Statistics Finland publishes new statistical data at 8 am on weekdays in its web service. The release times of statistics are given in advance in the release calendar available in the web service. The data are public after they have been updated in the web service. 

Further information: Publication principles for statistics at Statistics Finland 

 

Data sharing

The released data are published monthly on the home page of the statistics as StatFin database tables.

Accessibility and clarity

Statistical data are published as database tables in the StatFin database. The database is the primary publishing site of data, and new data are updated first there. When releasing statistical data, existing database tables can be updated with new data or completely new database tables can be published.   

In addition to statistical data published in the StatFin database, a release on the key data is usually published in the web service. If the release contains data concerning several reference periods (e.g. monthly and annual data), a review bringing together these data is published in the web service. Database tables updated at the time of publication are listed both in the release and in the review. In some cases, statistical data can also be published as mere database releases in the StatFin database. No release or review is published in connection with these database releases. 

Releases and database tables are published in three languages, in Finnish, Swedish and English. The language versions of releases may have more limited content than in Finnish.   

Information about changes in the publication schedules of releases and database tables and about corrections are given as change releases in the web service. 

 

Data revision - policy

Revisions – i.e. improvements in the accuracy of statistical data already published – are a normal feature of statistical production and result in improved quality of statistics. The principle is that statistical data are based on the best available data and information concerning the statistical phenomenon. On the other hand, the revisions are communicated as transparently as possible in advance. Advance communication ensures that the users can prepare for the data revisions.

The reason why data in statistical releases become revised is often caused by the data becoming supplemented. Then the new, revised statistical figure is based on a wider information basis and describes the phenomenon more accurately than before.

Revisions of statistical data may also be caused by the calculation method used, such as annual benchmarking or updating of weight structures. Changes of base years and used classifications may also cause revisions to data.

Cost index of civil engineering works is not revised.

Quality assessment

The quality of the cost index of civil engineering works is evaluated in several different stages of the statistical process. Changes in the unit level data of the statistics are examined monthly and the correctness of exceptional data is determined. In connection with base year revisions, the background team approves the weight structure and sub-indices of the index.

Quality assurance

Quality management requires comprehensive guidance of activities. The quality management framework of the field of statistics is the European Statistics Code of Practice (CoP). The frameworks complement each other. The quality criteria of Official Statistics of Finland are also compatible with the European Statistics Code of Practice. 

Further information: Quality management | Statistics Finland (stat.fi) 
 

User access

Data are released to all users at the same time. Statistical data may only be handled at Statistics Finland and information on them may be given before release only by persons involved in the production of the statistics concerned or who need the data of the statistics concerned in their own work before the data are published. 

Further information: Publication principles for statistics 

Unless otherwise separately stated in connection with the product, data or service concerned, Statistics Finland is the producer of the data and the owner of the copyright. The terms of use for statistical data. 
 

Statistical experts

Liina Arhosalo
Senior Statistician
029 551 3612