Namibia Household Income and Expenditure Survey 1993-1994
Namibia, 1993 - 1994
Central Statistics Office
Last modified
January 15, 2019
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Identification
Title
Namibia Household Income and Expenditure Survey 1993-1994
Countries
| Name | Abbreviation |
|---|---|
| Namibia | NAM |
idno
NAM_NSA_1993_NHIES
Study notes
The 1993/94 Namibia Household Income and Expenditure Survey (NHIES) is the first module of the National Household Survey Programme endorsed by the Government in 1993, a follow-up of the 1991 Population and Housing Census and represents one more step in providing useful statistics for charting and assessing the socio-economic development of the Namibian society. This programme is an integrated part of A Five-Year Development Plan of Statistics in Namibia. The purpose of the study is to highlight the living conditions of the Namibian people with the emphasis on the distribution of the economic resources among the Namibian households. The study provides a basic description of the living conditions in Namibia concerning economic activity, housing and infrastructure, possession of capital goods and property, economic standard as well as consumption and expenditure patterns.
Kind of data
Sample survey data [ssd]
Unit of analysis
- Individuals
- Households
- Households
Version
Version
Version 1.0: Edited, anonymous datasets for public distribution.
Coverage
Geographic coverage
National coverage
Unit of analysis
- Individuals
- Households
- Households
Universe
The 1993/94 Namibia Household Income and Expenditure Survey covered all private households in Namibia. Institutional households (like hospitals, hostels, barracks and prisons) are not included in the NHIES.
Producers and sponsors
Producer(s)
| Name | Affiliation | Role |
|---|---|---|
| The United Nations Development Programme | Technical Support for Establishment of the CSO | |
| Government of Sweden | Technical Support for Establishment of the CSO | |
| Government of the United Kingdom | Technical Support for Establishment of the CSO |
Other acknowledgement(s)
| Name | Affiliation | Role | |
|---|---|---|---|
| Vekondja Tjikuzu | Survey and Cartographic Unit | ||
| John de Wet | Survey and Cartographic Unit | ||
| Staffan Wahlström | Survey and Cartographic Unit | ||
| Alvis Weerasinghe | Survey and Cartographic Unit | ||
| Ottillie Iiyambo-Mwazi | Data Processing Unit | ||
| Onno Amutenya | Data Processing Unit | ||
| Bertil Georgsson/Soe Paing | Data Processing Unit | ||
| Sammy Kinyanjui | Data Processing Unit |
Sampling
Sampling procedure
There are essentially two sampling procedures that were followed in the NHIES 1993/94. One for Walvis Bay and one for the rest of Namibia. These will be addressed in turn.
The NHIES 1993/94 for most of Namibia follows a two stage sample design, taking random draws of geographical areas before randomly selecting households within that area. To do this, the Central Statistics Office (CSO), under the National Planning Commission (NPC), had to first develop a master sample frame.
To develop this master sample frame, a set of geographical areas, Primary Sampling Units (PSUs), was created and contained, on average, between 80 and 200 households. These areas were built from the Enumeration Areas (EAs) prepared for the 1991 Population and Housing Census. Small EAs were combined with adjacent EAs to form PSUs of sufficient size. The rule applied was that the number of households in a PSU according to the 1991 Population and Housing Census should be at least 80 households. About 1300 of the 1695 PSUs are made up of single EAs from the 1991 Population and Housing Census while about 400 PSUs are formed by joining two or more EAs. The 1695 PSUs, covering the whole of Namibia (except the Walvis Bay area), were separated into strata of PSUs by region and by rural, small urban and urban areas. The stratification into rural, small urban and urban areas was based on a classification of enumeration areas conducted during the preparations of the 1991 Population and Housing Census. (Note: A different definition of rural and urban areas is used in the statistical reporting from the 1991 Population and Housing Census and the HIES.) The urban areas in the Khomas region and some urban areas in the Otjozondjupa region were further stratified into high income and middle/low income areas. In this way 32 strata were created for the sampling of PSUs As a result of the way the PSUs were created, the number of PSUs of the master sample frame in each region and in each stratum is roughly proportional to the number of households in the region and in the stratum respectively as estimated in the 1991 Population and Housing Census.
Having developed the master sample frame, the NHIES 1993/94 was sampled according to a Probability Proporitional to Size (PPS) of PSUs method in the first stage and a fixed size equal probability sample of households in each selected PSU in the seond. 192 PSUs were selected in the first stage as the master sample.
Initially the master sample was proportionally allocated over the strata in the master sample frame according to the number of households in the 1991 Population and Housing Census. However, some modifications of the allocation were made based on the following:
- The variation between households in income level seems to be generally larger in the urban areas than in the rural areas.
- The survey costs are considerably lower in the urban areas.
- There should be at least 10 PSUs sampled from each region to allow for reasonably good statistics from each region.
It was deemed necessary to have a slight oversampling in urban areas and in one region (Omaheke). A proportional allocation of the 192 PSUs over urban/rural areas gave 66 urban and 126 rural PSUs. But, given the above specifications, the selection of the master sample resulted into 81 urban and 111 rural PSUs.
In the second stage, households were selected from the chosen PSUs. A list of households for each PSU was prepared during a separate listing exercise. The listing was carried out as closely as possible to the start of the data collection in a certain PSU i.e. the month before the NHIES survey month of the PSU. The list of households in the PSU was used as the sampling frame for the selection of households and a systematic equal probability random sample of 24 households from each PSU was drawn.
As initially mentioned, sampling was done slightly differently in Walvis Bay. This is because the region was not integrated in Namibia until 1 March 1994 and could therefore not be included in the NHIES before that date. For planning and logistic reasons Walvis Bay was included in the survey somewhat later - from May 1994. This means that Walvis Bay was included in the NHIES during the last six months of the survey year. The sampling procedure was different from the rest of Namibia. In Walvis Bay the municipality authorities have for administrative purposes created computerized registers of the households in all the three main town areas - Central Walvis Bay (incl. Langstrand), Kuisebmund and Narraville. Most of the households in Walvis Bay are covered by these registers. There are some areas, however, which are not covered by the administrative registers. These areas are the hostel areas of Walvis Bay and the area along the Kuiseb river where the Topnaar population lives. To cover also these population groups, CSO conducted listing of the households in these areas. For security reasons all the hostel areas could not be listed but some areas had to be excluded from the HIES. The number of listed households in the hostel areas was 99 and probably about the same number of households was not listed. The number of Topnaar households listed was 73.
Altogether 144 households from Walvis Bay were selected by mainly a stratified one-stage sample design to be included in the NHIES sample. 24 households were sampled during each of the six months (6 * 24 = 144). Separate strata were defined for Central Walvis Bay (incl. Langstrand), Kuisebmund (excl. the hostel areas), Narraville, the hostel areas and the Topnaar population and altogether 36, 54, 36, 6 and 12 households respectively were sampled from each stratum. (During May-July 1994 10 households were selected each month in Kuisebmund excluding the hostel areas. During August-October 1994 only 8 households were selected in Kuisebmund excluding the hostel areas while 2 households were selected in the hostel areas.)
The NHIES 1993/94 for most of Namibia follows a two stage sample design, taking random draws of geographical areas before randomly selecting households within that area. To do this, the Central Statistics Office (CSO), under the National Planning Commission (NPC), had to first develop a master sample frame.
To develop this master sample frame, a set of geographical areas, Primary Sampling Units (PSUs), was created and contained, on average, between 80 and 200 households. These areas were built from the Enumeration Areas (EAs) prepared for the 1991 Population and Housing Census. Small EAs were combined with adjacent EAs to form PSUs of sufficient size. The rule applied was that the number of households in a PSU according to the 1991 Population and Housing Census should be at least 80 households. About 1300 of the 1695 PSUs are made up of single EAs from the 1991 Population and Housing Census while about 400 PSUs are formed by joining two or more EAs. The 1695 PSUs, covering the whole of Namibia (except the Walvis Bay area), were separated into strata of PSUs by region and by rural, small urban and urban areas. The stratification into rural, small urban and urban areas was based on a classification of enumeration areas conducted during the preparations of the 1991 Population and Housing Census. (Note: A different definition of rural and urban areas is used in the statistical reporting from the 1991 Population and Housing Census and the HIES.) The urban areas in the Khomas region and some urban areas in the Otjozondjupa region were further stratified into high income and middle/low income areas. In this way 32 strata were created for the sampling of PSUs As a result of the way the PSUs were created, the number of PSUs of the master sample frame in each region and in each stratum is roughly proportional to the number of households in the region and in the stratum respectively as estimated in the 1991 Population and Housing Census.
Having developed the master sample frame, the NHIES 1993/94 was sampled according to a Probability Proporitional to Size (PPS) of PSUs method in the first stage and a fixed size equal probability sample of households in each selected PSU in the seond. 192 PSUs were selected in the first stage as the master sample.
Initially the master sample was proportionally allocated over the strata in the master sample frame according to the number of households in the 1991 Population and Housing Census. However, some modifications of the allocation were made based on the following:
- The variation between households in income level seems to be generally larger in the urban areas than in the rural areas.
- The survey costs are considerably lower in the urban areas.
- There should be at least 10 PSUs sampled from each region to allow for reasonably good statistics from each region.
It was deemed necessary to have a slight oversampling in urban areas and in one region (Omaheke). A proportional allocation of the 192 PSUs over urban/rural areas gave 66 urban and 126 rural PSUs. But, given the above specifications, the selection of the master sample resulted into 81 urban and 111 rural PSUs.
In the second stage, households were selected from the chosen PSUs. A list of households for each PSU was prepared during a separate listing exercise. The listing was carried out as closely as possible to the start of the data collection in a certain PSU i.e. the month before the NHIES survey month of the PSU. The list of households in the PSU was used as the sampling frame for the selection of households and a systematic equal probability random sample of 24 households from each PSU was drawn.
As initially mentioned, sampling was done slightly differently in Walvis Bay. This is because the region was not integrated in Namibia until 1 March 1994 and could therefore not be included in the NHIES before that date. For planning and logistic reasons Walvis Bay was included in the survey somewhat later - from May 1994. This means that Walvis Bay was included in the NHIES during the last six months of the survey year. The sampling procedure was different from the rest of Namibia. In Walvis Bay the municipality authorities have for administrative purposes created computerized registers of the households in all the three main town areas - Central Walvis Bay (incl. Langstrand), Kuisebmund and Narraville. Most of the households in Walvis Bay are covered by these registers. There are some areas, however, which are not covered by the administrative registers. These areas are the hostel areas of Walvis Bay and the area along the Kuiseb river where the Topnaar population lives. To cover also these population groups, CSO conducted listing of the households in these areas. For security reasons all the hostel areas could not be listed but some areas had to be excluded from the HIES. The number of listed households in the hostel areas was 99 and probably about the same number of households was not listed. The number of Topnaar households listed was 73.
Altogether 144 households from Walvis Bay were selected by mainly a stratified one-stage sample design to be included in the NHIES sample. 24 households were sampled during each of the six months (6 * 24 = 144). Separate strata were defined for Central Walvis Bay (incl. Langstrand), Kuisebmund (excl. the hostel areas), Narraville, the hostel areas and the Topnaar population and altogether 36, 54, 36, 6 and 12 households respectively were sampled from each stratum. (During May-July 1994 10 households were selected each month in Kuisebmund excluding the hostel areas. During August-October 1994 only 8 households were selected in Kuisebmund excluding the hostel areas while 2 households were selected in the hostel areas.)
Deviations from sample design
There were numerous issues related to coverage and data collection. These are extensively documented in Section 9 of the Technical and Administrative Report.
Response rate
The overall response rate for the 1993/94 NHIES was 92.5 percent.
Weighting
The weighting variable included in the NHIES is inverse to the inclusion probability for each sample. The weighting variable varies between a minimum of roughly 6.08 and a maximum of 245.3. For more detailed on weighting users are encouraged to consult the 1993/1994 Namibia Household Income and Expenditure Survey Administrative and Technical Report. Section 5.3 contains a lot of information on the weighting procedure. Please not that in the household datafile the weighting variable is called "rf". Additionally, there are the variables "rf1" and "rf4" which are alternative weights as explained in the Administrative and Technical Report
Data Collection
Dates of collection
| Start | End | Cycle |
|---|---|---|
| 1993-11-01 | 1994-10-01 |
Mode of data collection
Face-to-face [f2f]
Data collection supervision
Initially, the field staff were divided into eight (8) teams of seven (7) interviewers and one (1) supervisor each. The seventh interviewer in each team did not work as a regular interviewer but served as an assistant to the supervisor. One original team of eight individuals was split into two smaller teams consisting of three (3) interviewers with one (1) supervisor operating in each of these regions. Therefore, even though originally eight teams were organised, during most of the survey year nine teams worked in the field of which two smaller teams in the Caprivi and Okavango regions. Altogether the field staff comprised nine supervisors responsible for a group of 55 interviewers countrywide.
With the reintegration of Walvis Bay in 1994, it was decided that this area should also be included in the HIES. Hence, starting from May 1, 1994, a new team of 3 interviewers and one supervisor was established to cover Walvis Bay. This brought the total of interviewers and supervisors to fifty-eight (58) and ten (10) respectively.
Each team of 1 supervisor and 7 interviewers was provided with two cars for transport. The smaller teams in Caprivi and Okavango were provided with one car each. No professional drivers were used to transport the field teams. But supervisors and to a certain extent also interviewers with driver's licences were used as drivers. In total, 16 cars of which about 10 were 4x4 cars were allocated to the field staff. Another 3 cars were allocated to the CSO head office staff for the monitoring and following-up of the field work.
Each team was allocated two Primary Sampling Units (PSUs) per month. Three interviewers were responsible for the data collection in each PSU. Each interviewer was given eight (8) consecutive sampled households and was responsible for the data collection from these households for a period of one month. The supervisor supplied each interviewer with a Sample Household Sheet for PSU - FORMS - (see annex 1 of the Administrative and Technical Report, section 0.5) containing information on the 8 households for that particular interviewer. The information in Form S was transferred from Form L and contained the necessary information to identify and find the selected households in the field.
All forms but the Daily Record Book were kept by the interviewer throughout the month the household participated in the survey. The supervisor visited his/her team regularly during the month to "spot-check" their performance. After finishing the survey in one month, the interviewers carried out the concluding field check procedure for each set of questionnaires, signed and delivered them to the supervisor in charge. The supervisor in turn carried out his/her checks and signed the questionnaires. The questionnaires - the FORMS - were then collected by the senior field supervisors around the middle of the month after the survey month for the transport to the Central Statistics Office (CSO) head office in Windhoek.
With the reintegration of Walvis Bay in 1994, it was decided that this area should also be included in the HIES. Hence, starting from May 1, 1994, a new team of 3 interviewers and one supervisor was established to cover Walvis Bay. This brought the total of interviewers and supervisors to fifty-eight (58) and ten (10) respectively.
Each team of 1 supervisor and 7 interviewers was provided with two cars for transport. The smaller teams in Caprivi and Okavango were provided with one car each. No professional drivers were used to transport the field teams. But supervisors and to a certain extent also interviewers with driver's licences were used as drivers. In total, 16 cars of which about 10 were 4x4 cars were allocated to the field staff. Another 3 cars were allocated to the CSO head office staff for the monitoring and following-up of the field work.
Each team was allocated two Primary Sampling Units (PSUs) per month. Three interviewers were responsible for the data collection in each PSU. Each interviewer was given eight (8) consecutive sampled households and was responsible for the data collection from these households for a period of one month. The supervisor supplied each interviewer with a Sample Household Sheet for PSU - FORMS - (see annex 1 of the Administrative and Technical Report, section 0.5) containing information on the 8 households for that particular interviewer. The information in Form S was transferred from Form L and contained the necessary information to identify and find the selected households in the field.
All forms but the Daily Record Book were kept by the interviewer throughout the month the household participated in the survey. The supervisor visited his/her team regularly during the month to "spot-check" their performance. After finishing the survey in one month, the interviewers carried out the concluding field check procedure for each set of questionnaires, signed and delivered them to the supervisor in charge. The supervisor in turn carried out his/her checks and signed the questionnaires. The questionnaires - the FORMS - were then collected by the senior field supervisors around the middle of the month after the survey month for the transport to the Central Statistics Office (CSO) head office in Windhoek.
Questionnaires
The contents of the NHIES set of questionnaires were mainly decided on by the statistical user community. The first user-producer meetings took place during March/April 1992 during the first short-term mission of two Swedish consultants. Users from the following institutions took part in these meetings: the National Planning Commission, the Ministry of Finance, the Ministry of Trade and Industry, the Ministry of Labour, the Ministry of Local Government and Housing, the Ministry of Lands, Resettlement and Rehabilitation , the Bank of Namibia, the Namibian Economic Policy Research Unit (NEPRU) and the Social Sciences Division of the University of Namibia. Based on the pilot survey experiences and other considerations, revisions of the NHIES design took place during July - August 1993. Major changes were made in the questionnaires. All of the questionnaires were translated into the major languages of Namibia.
The main forms were:
- FORM I: Particulars on Individuals and Households. Filled in at the first interview visit which normally took place the week before the survey month.
- FORM II: Daily Record Book. Given to the household at the first visit. The Daily Record Book. The household was urged to record all their transactions on a daily basis in the book. If no literate person was available in the household or its proximity, frequent visits had to be paid by the interviewer. The first interview visit was followed by weekly visits to the household for collecting data on transactions.
- FORM III: Cash disbursement and Receipts. Transactions in cash recorded by the household were transferred by the interviewers on a weekly basis. The interviewer also regularly probed the households for cash transactions which they might have forgotten to record in the Daily Record Book.
- FORM IV: Transactions in Kind. The interviewer also probed the households for in kind transactions which they might have forgotten to record in the Daily Record Book.
- FORM V: Household Opinions. Consists of a module about household opinions concerning how to improve the economic well-being of the households. The Form V interview took place at the last interview visit after the survey month when the data collection concerning all other forms was ready.
The main forms were:
- FORM I: Particulars on Individuals and Households. Filled in at the first interview visit which normally took place the week before the survey month.
- FORM II: Daily Record Book. Given to the household at the first visit. The Daily Record Book. The household was urged to record all their transactions on a daily basis in the book. If no literate person was available in the household or its proximity, frequent visits had to be paid by the interviewer. The first interview visit was followed by weekly visits to the household for collecting data on transactions.
- FORM III: Cash disbursement and Receipts. Transactions in cash recorded by the household were transferred by the interviewers on a weekly basis. The interviewer also regularly probed the households for cash transactions which they might have forgotten to record in the Daily Record Book.
- FORM IV: Transactions in Kind. The interviewer also probed the households for in kind transactions which they might have forgotten to record in the Daily Record Book.
- FORM V: Household Opinions. Consists of a module about household opinions concerning how to improve the economic well-being of the households. The Form V interview took place at the last interview visit after the survey month when the data collection concerning all other forms was ready.
Data collector(s)
| Name | Abbreviation | Affiliation |
|---|---|---|
| Central Statistics Office | CSO | National Planning Commission |
Data Processing
Data editing
Editing, coding and data entry of the data collected in the field was conducted by temporary staff at the Data Processing Unit and the Survey and Cartographic Unit of the CSO Head Office in Windhoek between December 1993 and August 1995. Further data cleaning and preparation of the data files was conducted by the professional team at the Survey and Cartographic Unit.
Certain automatic imputations were also included in the program. These automatic imputations dealt with codes for non-response and not-applicable. There were two separate processes of data cleaning and editing conducted. The details of the data editing and cleaning process are detailed fully, for each edited variable, in the Technical and Administrative Report Section 7.
Certain automatic imputations were also included in the program. These automatic imputations dealt with codes for non-response and not-applicable. There were two separate processes of data cleaning and editing conducted. The details of the data editing and cleaning process are detailed fully, for each edited variable, in the Technical and Administrative Report Section 7.
Data access
Access authorities
| Name | Affiliation | URI | |
|---|---|---|---|
| Namibian Statistics Agency | Government of the Republic of Namibia | info@nsa.org.na | http://www.nsa.org.na/ |
Access conditions
The dataset has been anonymized and is available as a Public Use Dataset. It is accessible to all for statistical and research purposes only, under the following terms and conditions:
1. The data and other materials will not be redistributed or sold to other individuals, institutions, or organizations without the written agreement of the Namibian Statistics Agency.
2. The data will be used for statistical and scientific research purposes only. They will be used solely for reporting of aggregated information, and not for investigation of specific individuals or organizations.
3. No attempt will be made to re-identify respondents, and no use will be made of the identity of any person or establishment discovered inadvertently. Any such discovery would immediately be reported to the Namibian Statistics Agency.
4. No attempt will be made to produce links among datasets provided by the Namibian Statistics Agency, or among data from the Namibian Statistics Agency and other datasets that could identify individuals or organizations.
5. Any books, articles, conference papers, theses, dissertations, reports, or other publications that employ data obtained from the Namibian Statistics Agency will cite the source of data in accordance with the Citation Requirement provided with each dataset.
6. An electronic copy of all reports and publications based on the requested data will be sent to the Namibian Statistics Agency.
1. The data and other materials will not be redistributed or sold to other individuals, institutions, or organizations without the written agreement of the Namibian Statistics Agency.
2. The data will be used for statistical and scientific research purposes only. They will be used solely for reporting of aggregated information, and not for investigation of specific individuals or organizations.
3. No attempt will be made to re-identify respondents, and no use will be made of the identity of any person or establishment discovered inadvertently. Any such discovery would immediately be reported to the Namibian Statistics Agency.
4. No attempt will be made to produce links among datasets provided by the Namibian Statistics Agency, or among data from the Namibian Statistics Agency and other datasets that could identify individuals or organizations.
5. Any books, articles, conference papers, theses, dissertations, reports, or other publications that employ data obtained from the Namibian Statistics Agency will cite the source of data in accordance with the Citation Requirement provided with each dataset.
6. An electronic copy of all reports and publications based on the requested data will be sent to the Namibian Statistics Agency.
Citation requirements
Use of the dataset must be acknowledged using a citation which would include:
- the Identification of the Primary Investigator
- the title of the survey (including country, acronym and year of implementation)
- the survey reference number
- the source and date of download
Example:
Namibia Central Statistics Office. Namibia Household Income and Expenditure Survey (NHIES) 1993-1994, Ref. NAM_NSA_1993_NHIES. Dataset downloaded from [url] on [date].
- the Identification of the Primary Investigator
- the title of the survey (including country, acronym and year of implementation)
- the survey reference number
- the source and date of download
Example:
Namibia Central Statistics Office. Namibia Household Income and Expenditure Survey (NHIES) 1993-1994, Ref. NAM_NSA_1993_NHIES. Dataset downloaded from [url] on [date].
Disclaimer and copyrights
Disclaimer
The user of the data acknowledges that the original collector of the data, the authorized distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
contacts
Contact(s)
| Name | Affiliation | URI | |
|---|---|---|---|
| Namibian Statistics Agency | Government of the Republic of Namibia | info@nsa.org.na | http://www.nsa.org.na/ |