Official name of the survey/data source:
Income and Property Distribution Survey (Inntekts- og Formuesundersokelsen 1979)

LIS name:
Norwegian Income Survey - 1979

Administrative unit responsible for the survey:
Central Bureau of Statistics.

Funding for the survey is provided for by the Norwegian Central Bureau of Statistics (CBS), which is allocated money from the ordinary state budget.

Funding for the Norwegian Income Survey is provided for by the budget of the Central Statistical Office. Copies of the original codebook and other documentation can be obtained from the Central Statistical Office - at the above address, Department for Income, Property and Tax Statistics.

Name of primary research group who analyzed the data. Address of research group: 

The principle users of the data collected in this survey are the Norwegian government and research institutions.

Between 1970 and 1982 the Income and Property Distribution Survey (IDS) was conducted every three years. From 1984 on the IDS has been conducted annually.

The first year during which the IDS was conducted was 1970, and was first made available as microdata in 1970.

While the survey from the 1970s used administrative records to establish household composition, the surveys from 1982 and later are based on personal interviews. For the years 1979, 1982, 1986 and 1990) the IDS was coordinated with "The Level of Living Survey (LLS)".

The main purpose of the survey is to provide information regarding the structure and distribution of income and property for households and individuals.

The public has access to the data only under the condition that the anonymity of individuals be insured, and an official permit to establish data registration be obtained.

The IDS microdata have been made available to the Luxembourg Income Study Project under the condition that the anonymity of repondents be maintained.

A bibliography of the most important publications based on the IDS data is provided in Appendix N. Also included in the bibliography in Appendix N is a list of the user documentation for the IDS data.

B POPULATION AND SAMPLE SIZE, SAMPLING METHODS back

The final stage sampling frame for the survey consists of the Central Population Register.

People living in institutions such as prisons, homes for the elderly, wards, etc. have been excluded form the survey.

Military personnel were included in the sampling frame, providing the person is considered to still belong to the household (i.e. having common board), otherwise they are excluded.

Foreign citizens are included if they were registered in the Central Population Register.

Once the sample was selected from the sampling frame, all sampling units were eligible for interview.

1. The Sample Design

A two stage sample design is employed in the IDS. In the first stage the whole country is divided into primary sampling units which correspond to the number of municipalities.

Municipalities with less than 3,000 inhabitants are collapsed such that every primary sampling unit (PSU) has at least 3,000 inhabitants.

The PSUs are then grouped in 10 regions. Municipalities with more than 30,000 inhabitants make up separate stratas, while the other municipalities are stratified according to a number of attributes such as industry and population size.

In the sampling design those municipalities which make up separate strata (those with over 30,00 inhabitants) are drawn with a 100% selection propability. The other municipalities have a probability of selection proportional to their size.

In the second stage a sample of persons is selected from the Central Population Register. There were equal selection probabilities of each group.

The survey unit was comprised of households which were defined as persons living in the same dwelling and having common board.

There were a total of 3,000,000 persons in the population from which the sample was selected. Unoccupied units were not excluded.

The total number of respondents who were actually surveyed was 9,366. When weighted, this amounts to 4,210,000 cases. The sample that was made available the LIS database was comprised of 10,414 cases. LIS was able to make available to its users 10,414 cases.

All geographic areas in the country were included in the sample design.

Estimates of sampling variability (standard errors) have not been computed for this survey.

C. MEASURES OF DATA QUALITY back

1. Item and Group Nonresponse Rates

For the income data the "response rate" is 100% (all income data are collected from administrative sources). For the interview on household composition the response rate was approximately 75%.

2. Reporting and Under-Reporting and Income Data Quality

An evaluation of the quality of the income data has been made by comparing the survey data with National Income Accounts, Tax Statistics, and Population Statistics.

3. Data Corrections and Adjustments

Adjustments to the original data have been made in the interests of improving data quality. No simulations, estimations, or imputations for income or tax values have been made.

4. General Assessment of Income Data Quality

Users of this data should be aware of the following three problems regarding the quality of the income data collected in this survey:

1. Income estimates derived from taxation records (i.e. income not reported to tax authorities). Tax evasions seems to occur in all segments of the income distribution, but more often among men than women, and more often among young than old, and probably more often among self employed than among salary earners.
2. Household composition estimates. However, more than 85% of households consist of only one family, which is identified by the Central Population register.
3. Data on occupational status are weak.

D. DATA COLLECTION AND ACQUISITION back

1. Method of Data Collection

The data were collected using a combination of modes, including questionnaires sent by mail, and telephone and personal interviews.

Participation in the survey was voluntary and the privacy of respondents was assured.

2. Structure of the Survey Instrument

A questionnaire was mailed to the individual selected (age 15 years and older), which asked about household composition. 

3. Survey Respondent Rules

Each household member was not required to answer the questions for himself/herself. Answers could be provided by other household members.

Respondents were not asked to consult or use pay records, tax returns, or other documents, because no income questions were included in the questionnaire or interview.

E. WEIGHTING PROCEDURES back

Survey weights have been assigned to each sample case. These weights were assigned in order to report macro-estimates (percentages) for income and population data, and in order to compare the survey data with data from the Central Population Register.

These weighting procedures helped adjust for missing data. The sum of the survey weights is equal to the total number of units in the sampling frame.

Estimates derived from the sample are representative of the total population as defined by the sampling frame.

F. DETERMINATION OF SURVEY UNIT MEMBERSHIP back

If a person is considered by the interviewer to belong to the household he or she is included.
Children born during the reference year year are included in the survey, as well as people who have died during that same period.
For households which were not surveyed, information on family composition obtained from the Central Population Register is accepted as valid.
The basic unit of aggregation which was used in this survey was household.
Households were defined as all people living in the same dwelling and having common board.
The overall sampling unit can be divided into subgroups in those situations where several families share the same housing unit.
The survey unit head was the head of household, and he/she was identified during the interview as the person having the largest gross income. In case of doubt it is the oldest person in the household.
In the household file only the head can be identified.

G. CHILDREN AND SPOUSES back

Persons less then 17 years old are considered to be "children." In some tables, however, unmarried persons living with their parents are regarded as children even though they are above the age of 17.
The survey does not provide information to distinguish between children of the unit head (or spouse), and children of some other household member, or of someone living outside the household.
The relationship between household members and the head can be established by using the family number from the Central Population Register.
In this survey spouses are defined using categories from administrative records and from tax returns.

H. AVAILABILITY OF BASIC SOCIAL AND DEMOGRAPHIC INFORMATION back

In Table 7.2 are summarized the basic social and demographic information which is available in the IDS.

Table 7.2
Basic Social and Demographic Information   

I. AVAILABILITY OF LABOUR MARKET INFORMATION back 

Labor force status information is available for the IDS. Labor force participation was defined in terms of economic activity. Information on the number of hours worked per week (or month, etc.) was not recorded. Available labor market information is summarized in Table 2.

Table 7.3:
Labor Market Information   

J. AVAILABILITY OF GEOGRAPHIC INFORMATION back

It is possible to identify the geographic location of the sampling units in this survey. The geographic categories which are used in this survey are region and size of municipality.

K. SOURCES AND AMOUNTS OF CASH INCOME back

Sources and amounts of income are recorded for an annual period. The amounts recorded were the actual amounts received. Income sources and amounts are recorded for persons.

L. TAXES back

Taxation information is available for the IDS.

M. BIBLIOGRAPHY OF MAIN PUBLICATIONS back

NNTEKTS- OG FORMUESSTATISTIKK 1987; INCOME AND PROPERTY STATISTICS 1987; 1987, CENTRAL BUREAU OF STATISTICS OF NORWAY, STATISTIK SENTRALBYRA.

INTERNE NOTATER; STATISTIK SENTRALBYRA; INNTEKTS- OGFORMUESUNDERSOKELSEN 1987; DOKUMENTASJON; REDIGIERT AV VIVAR PEDARSEN.