The 1999 Tanzania Reproductive and Child Health Survey (TRCHS) is the fourth in a series of national sample surveys. The first was the 1991-92 Tanzania Demographic and Health Survey (TDHS), which was followed by the Tanzania Knowledge, Attitudes and Practices Survey (TKAP) in 1994 and then by the 1996 Tanzania Demographic and Health Survey (TDHS).
The Tanzania Demographic and Health Survey (TDHS) is part of the worldwide Demographic and Health Surveys (DHS) programme, which is designed to collect data on fertility, family planning, and maternal and child health.
The primary objective of the 1999 TRCHS was to collect data at the national level (with breakdowns by urban-rural and Mainland-Zanzibar residence wherever warranted) on fertility levels and preferences, family planning use, maternal and child health, breastfeeding practices, nutritional status of young children, childhood mortality levels, knowledge and behaviour regarding HIV/AIDS, and the availability of specific health services within the community.1 Related objectives were to produce these results in a timely manner and to ensure that the data were disseminated to a wide audience of potential users in governmental and nongovernmental organisations within and outside Tanzania. The ultimate intent is to use the information to evaluate current programmes and to design new strategies for improving health and family planning services for the people of Tanzania.
Kind of Data
Sample survey data
Unit of Analysis
- Children under five years
- Women age 15-49
- Men age 15-59
The 1999 Reproductive and Child Health Survey/ Demographic and Health Survey covered the following topics:
- Birth Registration
- Child Labor
- Early Childhood Education
- GPS/Georeferenced-Global Positioning System or Georeferenced Data
- HIV Behavior
- HIV Knowledge-Questions assess knowledge/sources of knowledge/ways to avoid HIV
- Iodine salt test
- Malaria/Bednet Questions
- Men's Survey
- Social Marketing
National. The sample was designed to provide estimates for the whole country, for urban and rural areas separately, and for Zanzibar and, in some cases, Unguja and Pemba separately.
Producers and sponsors
National Bureau of Statistics (NBS)
Macro International Inc.
Ministry of Health
Technical advice and logistical support
United States Agency for Intemational Development
United Nations Population Fund - Tanzania
United Nations Children's Fund - Tanzania
The TRCHS used a three-stage sample design. Overall, 176 census enumeration areas were selected (146 on the Mainland and 30 in Zanzibar) with probability proportional to size on an approximately self-weighting basis on the Mainland, but with oversampling of urban areas and Zanzibar. To reduce costs and maximise the ability to identify trends over time, these enumeration areas were selected from the 357 sample points that were used in the 1996 TDHS, which in turn were selected from the 1988 census frame of enumeration in a two-stage process (first wards/branches and then enumeration areas within wards/branches). Before the data collection, fieldwork teams visited the selected enumeration areas to list all the households. From these lists, households were selected to be interviewed. The sample was designed to provide estimates for the whole country, for urban and rural areas separately, and for Zanzibar and, in some cases, Unguja and Pemba separately. The health facilities component of the TRCHS involved visiting hospitals, health centres, and pharmacies located in areas around the households interviewed. In this way, the data from the two components can be linked and a richer dataset produced.
See detailed sample implementation in the APPENDIX A of the final report.
In all, 3,826 households were selected for the sample, out of which 3,677 were occupied. Of the households found, 3,615 were interviewed, representing a response rate of 98 percent. The shortfall is primarily due to dwellings that were vacant or in which the inhabitants were not at home despite of several callbacks.
In the interviewed households, a total of 4,118 eligible women (i.e., women age 15-49) were identified for the individual interview, and 4,029 women were actually interviewed, yielding a response rate of 98 percent. A total of 3,792 eligible men (i.e., men age 15-59), were identified for the individual interview, of whom 3,542 were interviewed, representing a response rate of 93 percent. The principal reason for nonresponse among both eligible men and women was the failure to find them at home despite repeated visits to the household. The lower response rate among men than women was due to the more frequent and longer absences of men.
The response rates are lower in urban areas due to longer absence of respondents from their homes. One-member households are more common in urban areas and are more difficult to interview because they keep their houses locked most of the time. In urban settings, neighbours often do not know the whereabouts of such people.
Dates of Data Collection
Data Collection Mode
Data Collection Notes
Competency was the guiding factor in recruiting interviewers. As with 1991-92, 1994, and 1996 surveys, the Ministry of Health was requested to secure the services of trained nurses to be interviewers in the 1999 TRCHS. A similar request was made to the Zanzibar Ministry of Health to provide nurses to serve as interviewers.
The training of field staff for the main survey was conducted over a three-week period from mid-August to the first week of September 1999, at the Golden Rose Hotel in Arusha Municipality. A total of 100 nurses were recruited and trained by experienced statisticians and demographers from the National Bureau of Statistics, with support from staff at Macro International Inc. and guest lecturers from the Arusha Regional Hospital and staff from the Tanzania Food and Nutrition Centre. Trial interviews were conducted in the nearby villages and in some parts of Arusha Municipality. Trainees also visited day care centres to gain experience in measuring children. Data processing staff participated in the training to acquaint themselves with the questionnaires. The training course consisted of instructions in interviewing techniques and field procedures, as well as a detailed review of items on the questionnaires. It also covered use of salt testing kits, weighing and measuring children, mock interviews between participants in the classroom, and practice interviews with real respondents in and around Arusha Municipality. During training, a series of assessment tests were given to the class. These tests were graded, and the results were used to select interviewers. Those who showed a high level of understanding of the questionnaires and were also able to detect errors in completed questionnaires were later chosen to be field editors.
Supervisors and editors participated in further training to discuss their duties and responsibilities. Ensuring data quality was emphasised. The supervisor was required to act as the leader of the field team and to be responsible for the well-being and safety of team members, as well as the completion of the assigned workload and the maintenance of data quality. Responsibilities of the editor included monitoring interviewer performance and checking all questionnaires for completeness and consistency. Close supervision of the interviewers and editing of completed questionnaires was emphasised to ensure accurate and complete data collection.
The fieldwork began the first week of September and continued until the third week of November 1999. Data collection for the 1999 TRCHS was implemented by ten teams, nine of which were composed of six female interviewers, one male interviewer, a field editor, a supervisor, and a driver. The tenth team was for quality control and was composed of a supervisor, two interviewers, and a driver.
The quality control team visited all the teams to check the quality of their work by reviewing completed questionnaires, observing interviews, and reinterviewing a subsample of households to check that the original interviews were completed and all eligible respondents were correctly identified. Problems found in one team were immediately communicated to other teams through the head office.
National Bureau of Statistics
The household survey component of the TRCHS involved three questionnaires:
1) a Household Questionnaire,
2) a Women’s Questionnaire for all individual women age 15-49 in the selected households, and
3) a Men’s Questionnaire for all men age 15-59.
The health facilities survey involved six questionnaires:
1) a Community Questionnaire administered to men and women in each selected enumeration area;
2) a Facility Questionnaire;
3) a Facility Inventory;
4) a Service Provider Questionnaire;
5) a Pharmacy Inventory Questionnaire; and
6) a questionnaire for the District Medical Officers.
All these instruments were based on model questionnaires developed for the MEASURE programme, as well as on the questionnaires used in the 1991-92 TDHS, the 1994 TKAP, and the 1996 TDHS. These model questionnaires were adapted for use in Tanzania during meetings with representatives from the Ministry of Health, the University of Dar es Salaam, the Tanzania Food and Nutrition Centre, USAID/Tanzania, UNICEF/Tanzania, UNFPA/Tanzania, and other potential data users. The questionnaires and manual were developed in English and then translated into and printed in Kiswahili.
The Household Questionnaire was used to list all the usual members and visitors in the selected households. Some basic information was collected on the characteristics of each person listed, including his/her age, sex, education, and relationship to the head of the household. The main purpose of the Household Questionnaire was to identify women and men who were eligible for individual interview and children under five who were to be weighed and measured. Information was also collected about the dwelling itself, such as the source of water, type of toilet facilities, materials used to construct the house, ownership of various consumer goods, and use of iodised salt. Finally, the Household Questionnaire was used to collect some rudimentary information about the extent of child labour.
The Women’s Questionnaire was used to collect information from women age 15-49. These women were asked questions on the following topics:
· Background characteristics (age, education, religion, type of employment)
· Birth history
· Knowledge and use of family planning methods
· Antenatal, delivery, and postnatal care
· Breastfeeding and weaning practices
· Vaccinations, birth registration, and health of children under age five
· Marriage and recent sexual activity
· Fertility preferences
· Knowledge and behaviour concerning HIV/AIDS.
The Men’s Questionnaire covered most of these same issues, except that it omitted the sections on the detailed reproductive history, maternal health, and child health. The final versions of the English questionnaires are provided in Appendix E.
Before the questionnaires could be finalised, a pretest was done in July 1999 in Kibaha District to assess the viability of the questions, the flow and logical sequence of the skip pattern, and the field organisation. Modifications to the questionnaires, including wording and translations, were made based on lessons drawn from the exercise.
All the questionnaires for the TDHS were returned to the National Bureau of Statistics for data processing, which consisted of office editing, coding of open-ended questions, data entry, and editing of computer-identified errors. All data were processed on microcomputers and a software programme developed for DHS surveys, called the Integrated System for Survey Analysis (ISSA). The data processing staff for the survey consisted of eight data entry operators, one editor and two supervisors who were staff of the National Bureau of Statistics. Data entry was 100 percent verified. Office editing and data processing activities were initiated immediately after the beginning of fieldwork and were completed in mid-January 2000.
Estimates of Sampling Error
The estimates from a sample survey are affected by two types of errors: (1) non-sampling errors, and (2) sampling errors. Non-sampling errors are the results of mistakes made in implementing data collection and data processing, such as failure to locate and interview the correct household, misunderstanding of the questions on the part of either the interviewer or the respondent, and data entry errors. Although numerous efforts were made during the implementation of the TRCHS to minimise this type of error, nonsampling errors are impossible to avoid and difficult to evaluate statistically.
Sampling errors, on the other hand, can be evaluated statistically. The sample of respondents selected in the TRCHS is only one of many samples that could have been selected from the same population, using the same design and expected size. Each of these samples would yield results that differ somewhat from the results of the actual sample selected. Sampling errors are a measure of the variability between all possible samples. Although the degree of variability is not known exactly, it can be estimated from the survey results.
A sampling error is usually measured in terms of the standard error for a particular statistic (mean, percentage, etc.), which is the square root of the variance. The standard error can be used to calculate confidence intervals within which the true value for the population can reasonably be assumed to fall. For example, for any given statistic calculated from a sample survey, the value of that statistic will fall within a range of plus or minus two times the standard error of that statistic in 95 percent of all possible samples of identical size and design.
If the sample of respondents had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the TRCHS sample is the result of a two-stage stratified design, and, consequently, it was necessary to use more complex formulae. The computer software used to calculate sampling errors for the TRCHS is the ISSA Sampling Error Module (SAMPERR). This module used the Taylor linearisation method of variance estimation for survey estimates that are means or proportions. The Jackknife repeated replication method is used for variance estimation of more complex statistics such as fertility and mortality rate
Note: See detailed sampling error calculation in the APPENDIX B of the final report.
Data Quality Tables
- Household age distribution
- Age distribution of eligible and interviewed women
- Completeness of reporting
- Birth by calendar years
- Reporting of age at death in days
- Reporting of age at death in months
Note: See these data quality tables in APPENDIX C of the final report.
Data and Data Related Resources
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
Disclaimer and copyrights
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.