About the Population and Housing Census 2001

1. Introduction

2. Production of the dataset

3. Contents

4. Quality

5. Documentation

6. Contact persons

1. Introduction

On 3 November 2001, Statistics Norway conducted a nationwide population and housing census (Census 2001). The primary objective of the census was to obtain a picture of the population and the living conditions in the Norwegian society.

2. Production of the dataset

Register data in Census 2001

The data used in Census 2001 is collected from

• Administrative and statistical registers
• Questionnaires (the housing census)
• on persons and geography is retrieved from administrative registers. Information on persons composing one family and one household is based on joint information from the Central Population Register (CPR) and from data collected by questionnaires (the housing forms). Information on housing (dwellings and buildings) is mainly gathered from the housing form supplemented with information from the Register of Ground Properties, Addresses and Buildings (GAB).

Population data

The population statistics system at Statistics Norway (Besys) is the most pivotal register in Census 2001. (In February 2006 the Besys was replaced by the Statistical Population Register). The most important source of data is the Central Population Register (CPR). The Office of the National Registrar, under the Directorate of Taxes, is responsible for population registration. Demographic data and information on residence and immigration background are retrieved from the population register.

Education data

The source for education data is Statistics Norway's Register of the Population's Highest Level of Education (BHU), in August 2002 replaced by the National Education Database (NUDB). The register is based on information from individual educational institutions as well as state and county authority data systems. The data system is more closely described in NOS C 645 Education statistics. Further information; please go to NUDB.

Labour market data

Labour market data is based on several registers and data systems. The most important of these are:

• The Register of Employees. Responsible: National Insurance Administration
• The Register of Wage Sums. Responsible: Directorate of Taxes
• The Tax Return Statistics. Mainly based on data from Directorate of Taxes
• The Register of Unemployed (SOFA-søker, replaced by ARENA). Responsible: The Norwegian Public Employment Service (Aetat)
• The Central Coordinating Register of Legal Entities and the Central Register of Establishments and Enterprises (business registers). Responsible: The Brønnøysund Register Centre and Statistics Norway

Further information on labour market data; please click here

Income data

Data is collected from Statistics Norway’s system for Income statistics for persons and families (IPF). In addition to the population register, this system is based on the following registers and statistical sources:

• The Tax Return Statistics (income). Mainly based on data from the Directorate of Taxes
• Tax Register for Personal Taxpayers (income). Responsible: Directorate of Taxes
• The Register of Wage Sums (income). Responsible: Directorate of Taxes
• Data from the National Insurance Administration (various benefits)
• Register of social assistance. Statistics Norway obtains data from the individual municipalities.
• Data from the State Educational Loan Fund (grants)
• Data from the Norwegian State Housing Bank (housing allowances)
• The Register of Inheritance Tax. Responsible: Ministry of Finance.

For further details go to Income statistics based on register data.

Data on national insurance and social assistance

Data for social security benefits is obtained from FD-Trygd, a longitudinal database of Statistics Norway. Pension data (long-term benefits) is obtained from monthly files from the National Insurance Administration; data for social assistance from annual files in Statistics Norway, which are based on reports from the individual municipalities.

For further details go to FD-trygd.

Data on private cars and driving licences

Data is primarily retrieved from the Register of Motor Vehicles and the Driving Licence Register. The Directorate of Public Roads in Norway is responsible for both registers. Data is also retrieved from the Register of Wage Sums for persons with the use of a company car.

Geographic variables

Information on addresses for residents, dwellings, workplaces and schools/educational institutions is retrieved from the address section of the GAB Register (responsibility of the Norwegian Mapping Authority). For classifications of municipalities and basic statistical unit the version as per 1 January 2002 is used.

Register data for dwellings

Information is retrieved from the buildings section of the GAB Register, which includes details of the building to which the dwelling belongs.

The housing census

The housing section of the census was conducted by means of a questionnaire. The questionnaire was sent to all families who were resident in Norway according to the Central Population Register, and was addressed to the oldest family member. The questionnaire is available in Norwegian by clicking here. For English translation of questionnaire, click here.

A separate census form was sent to students who had applied for grants for students living away from home in 2001 according to the State Educational Loan Fund. The purpose of sending the questionnaire to students living away from home was to obtain information on their dwellings at their place of study (actual place of residence).

Separate questionnaires were also sent to all homes for the elderly and nursing homes in Norway. The managers were asked to provide the names and dates of birth of all residents at their institution. No further details on dwellings were collected for these residents. Persons listed on the institution’s questionnaire were exempt from filling in the separate housing forms.

3. Contents

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Statistical unit

Person, couple, family, household and dwelling are the units in the Census 2001. In the following you find a brief documentation of definitions.

Person

The census comprises all persons considered resident in Norway (according to the CPR) on 3rd November 2001, see The Population Registration Act of 16th January 1970 (with later amendments) and its provisions from 1994.

Couple

Two persons are considered a couple when they belong to the same household and are married to each other, are registered partners or cohabitants i.e., are living together without being married or without having a registered partnership. To be considered cohabitants the couple must belong to the same household, and in addition have children in common or respond in the housing questionnaire that they are cohabiting.

Family

A family consists of persons resident in the same dwelling and related to each other as spouse, registered partner, cohabitant, and/or parent and children (regardless of the child's age). At most, a family may consist of two subsequent generations and one couple only.

Please note that this definition is slightly different from the one that is used in the current statistics on families for 2001, because the basis for the data in the latter makes it impossible to identify cohabitants if they do not have children in common. These persons are therefore not considered as belonging to the same family.

In the UN and EU recommendations on population and housing censuses the concept family nucleus is used. A family nucleus is defined as a family with two or more persons. For international comparisons Statistics Norway report on the unit family nucleus.

Household

A household consists of persons that are permanently resident in the same dwelling (housing unit) or institution. Such a household is called a dwelling household. Census 2001 does not supply any information about housekeeping units i.e. persons living in the same dwelling with joint board.

A private household comprises persons resident in the same dwelling, where this dwelling is not an institution. An institutional household comprises persons who have board, lodging, care and nursing at an institution. Employees that are resident in an institution are always considered resident in a private household. Census 2001 does not provide any statistics for institutional households, however the number of persons not living in private households are given. This group is referred to as resident in other households and comprises persons resident in institutional households as well as persons of no fixed address.

Households may comprise one or more families. Persons belonging to the same family also belong to the same household. If persons who do not belong to the same family are to be considered a household, they have to be registered at the same CPR address and they need to have confirmed in the questionnaire that they live together. This means that unmarried students usually living away from home, but registered at their parents' address, are considered part of their parents' household. Only persons that are registered as residents at an institution are considered as belonging to a collective household. Many persons who live in institutions, for e.g., old people's homes and nursing homes, are registered as resident in a private dwelling (together with their spouse).

Dwelling

A dwelling is defined as one or more rooms that has been built or rebuilt for the purpose of being used as a round the year dwelling for one or more persons. It must be possible to have access to the room/rooms without having to go through another dwelling. Therefore, a dwelling is for instance a detached house, a row house, an apartment in a twin house or block of flats or a bed-sitter. A one-room flat in a private house is considered a dwelling as long as it has independent access.

Variable summary

The Census 2001 consists of variables on persons referring to demography, place of living, immigration, highest completed education, ongoing education, labour market, income, private cars and driving licences. Further there are variables describing families, couples, households, dwellings and buildings. There are also variables describing geography. If not otherwise mentioned, the geographical groupings refer to the standard classification of municipalities as per 1 January 2002. For detailed information on the main variables please go to Documents 2005/2 "The Population and Housing Census Handbook 2001".

In this summary the variables are divided by subject. Variables that would allow direct identification of units can be supplied as serial number only. Some other variables can be supplied on an aggregate level only for grouping purposes. This is specified for the relevant variables underneath.

Variable names (labels) and definitions are available in Norwegian only.

Subjects

Persons

Families

Households

Education

Labour market, census week

Labour market, census year

Unemployment

Place of work, census week

Place of work, census year

Social security

Economy, persons

Economy, households

Cars and driving licenses

Dwellings

Adjustments of data on dwellings

Persons

Families

Households

Education

Labour market, census week

Labour market, census year

Unemployment

Place of work, census week

Place of work, census year

Social security

Economy, persons

Economy, households

Cars and driving licenses

Dwellings

Adjustments of data on dwellings

4. Quality

Errors and uncertainties of the results

Unit non-response

When the form is missing or completely useless, it is referred to as unit non-response. As for 7 percent of the families addressed, Statistics Norway did not receive any response, as a total it was lacking information for nearly 140 000 households. Some 40 000 forms were returned from the Post Services largely due to the fact that the contact persons were not reached at their CPR address. Another 93 000 forms were never returned even after the second reminder was sent. For the rest the contact person was living in an institution, he or she was a student living abroad or the contact person/family was exempted. The non-response is characterised by a large number of families consisting of one person only, few married couples, few cohabitants having children in common and few families with children. Further the percentage of non-response is smaller for families living in detached houses than for families living in other types of dwellings.

Item non-response

Item non-response occurs when certain questions are not answered at all or when we are unable to interpret the answers. In general the degree of this type of non-response in the census is low. The extent of item non-response differs from question to question. These discrepancies are probably related to the degree of difficulty that the respondent has when answering the question. In other cases it might be because the respondent do not want to give the information asked for. In the case of item non-response values have been imputed according to answers for randomly selected dwellings in the same strata (strata by geographical unit, type of building, type of household etc). The size of these errors is probably minimal and is of no significance for the interpretation of figures and comparability with other statistics. Further information is to be found in Norwegian in NOS D316 "Folke- og boligtellingen 2001 Hele landet" and in the individual reports per county/municipality which you will find here (in Norwegian). English abstracts divided by items can be found here.

Information on dwellings

Due to different definitions and methods for collecting data it was found considerable deviations between the census and the survey of living conditions. For the questions about number of rooms only 40 percent of the respondents have given the same answer in the census and the survey. The information on dwellings of 3 rooms and that of 6 rooms ore more, is of good quality. The number of dwellings of 1 and 5 rooms seems to be overestimated and those with 2 and 4 rooms seem to be underestimated in the census.

For information on floor space approximately 50 percent of the answers in the survey and the census are corresponding to each other. For dwellings between 40 and 99 square meters there is no significant systematical errors. However the number of smaller dwellings seems to be overestimated, and for dwellings larger than 100 square meters there are considerable deviations.

For tenure status there is no significiant deviation between the survey and the census.

Approximately 90 percent of the respondents live in dwellings located in the same type of building according the census and the survey. In spite of this, detached houses as well as blocks of flats are underestimated in the census.

For further information see NOT 2003/47. Kvaliteten i boligdelen av Folke- og boligtellingen (in Norwegian only).

Information on households

The information on place of residence collected in the census differs from the corresponding information in of the survey of living conditions. The census is based on formal address (CPR address) while the survey gives de facto address of living. The difference is mainly observed for persons in the age of 20 to 35 years (mainly students living away from home). As a consequence the per cent of households with adult children is overestimated in the census, while the per cent of households consisting of one-person households and couples without children is underestimated.

Some main results from analysing the deviation:

• Number of de facto household is at least 100 000 more than according to the census
• For nearly 50 per cent of the households with resident adult children according to the census, the children are actually living at another address
• The number of one- and two-persons households is underestimated; households of three and more persons are overestimated in the census.
• Number of cohabiting couples is underestimated, especially for persons in the age of 20 to 29 years

Information on labour market

The information used in the census is the same as in the register-based labour market statistics. The quality of the census statistics is measured by comparing with the Labour Force Survey (LFS) on both macro and micro level. In general the LFS is considered giving the more correct results in spite of known errors in the LFS. The quality of the information on employment in the census is considered relatively good compared with the LFS data.

In the analysis of the measurement errors of the register-based labour market statistics, the Labour Force Survey is assumed to be correct, even though it is known that this is not always the case.

The analyses show that:

• The bias is relatively small for employment by gender, counties and industrial classification, (Nace).
• The quality of the census information on employment among people aged 25-66 years seems to be high. The bias is however relatively large for employment among young people (20-24 years) and for older people (67-74 years). This is probably caused by difficulties with classification in the registers for people with part time employment.
• The bias is relatively small for employed persons classified by weekly working hours on macro level. However, on a micro level the bias is large for persons working less than 30 hours a week.
• For non-employed persons (unemployed, students, pensioners) the bias is rather large compared to data from the LFS
• In the register-based statistics there are less persons employed in the public sector than according to the LFS. This is probably caused by the selection of main employment in the register-based statistics and due to errors in coding of sector, especially for public enterprises.

Punctuality

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Time of reference

Demography and dwellings 3 November 2001

Labour force data 29 October to 4 November 4^th 2001 (census week) and the year 2001

Income data Year 2001

Education 1 October 2001

Municipalities If not mentioned otherwise according to the classification as per 1 January 2002

Comparability

See NOS D316 "Folke- og boligtellingen 2001 Hele landet" (Norwegian only) and "About the statistics"

5. Documentation

NOS D316 Folke- og boligtellingen 2001 Hele landet

NOT 2004/04. Kvaliteten i arbeidsmarkedsdelen i Folke- og boligtellingen 2001.

NOT 2003/78 Kvaliteten i husholdningsdelen i folke- og boligtellingen 2001.

NOT 2003/47. Kvaliteten i boligdelen av Folke- og boligtellingen.

NOT 2000/24 Dokumentasjon av BESYS -befolkningsstatistikksystemet. Befolkningsendringer i 1998 og befolkningsbasen (BEBAS) 1. januar 2000

NOT 2004/23 Håndbok for Folke- og boligtellingen 2001

DOC 2005/2 The Population and Housing Census Handbook 2001

NOT 2005/4 Dokumentasjon av FoB2001. Spesifikasjoner, bearbeiding, flytdiagram for spørreskjemadelen av tellingen. Del I.

NOT 2005/5 Dokumentasjon av FoB2001 Spesifikasjoner, bearbeiding, flytdiagram for spørreskjemadelen av tellingen. Del II Vedlegg.

RAPP 2006/31 Kvaliteten i Folke- og boligtellingen 2001.

NOT 2006/46 FOB2001. Dokumentasjon av logistikk og svartjeneste.

6. Contact persons

Britt Elin Bråten tel: +47 62 88 51 43, e-mail bre@ssb.no

Harald Utne tel: +47 21 09 47 84, e-mail hut@ssb.no

2007 © Statistics Norway