TZA_2004_DHS_v01_M
Demographic and Health Survey 2004-2005
Name | Country code |
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Tanzania | TZA |
Demographic and Health Survey (standard) - DHS IV
The 2004-05 Tanzania Demographic and Health Survey (TDHS) is the sixth in a series of national sample surveys conducted in Tanzania to measure levels, patterns, and trends in demographic and health indicators. The first one was the 1991-92 TDHS, which was followed by the Tanzania Knowledge, Attitudes, and Practices Survey (TKAPS) in 1994, the 1996 TDHS, the 1999 Tanzania Reproductive and Child Health Survey (TRCHS), and the 2003-04 Tanzania HIV/AIDS Indicator Survey (THIS).
Sample survey data
The 2004-2005 Demographic and Health Survey covered the following topics:
HOUSEHOLD
WOMEN
MEN
The sample for the 2004-05 TDHS was designed to provide estimates for the entire country, for urban and rural areas of the Mainland, and for Zanzibar. Additionally, the sample design allowed for specific indicators, such as contraceptive use, to be calculated for each of the 26 regions.
Name |
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National Bureau of Statistics (NBS) |
Name | Role |
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ORC Macro | Technical assistance |
Name | Role |
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United States Agency for Intemational Development | Financial assistance |
The sample for the 2004-05 TDHS was designed to provide estimates for the entire country, for urban and rural areas of the Mainland, and for Zanzibar. Additionally, the sample design allowed for specific indicators, such as contraceptive use, to be calculated for each of the 26 regions.
To estimate geographic differentials for certain demographic indicators, this report collapses the regions of mainland Tanzania into seven geographic zones. Although these are not official administrative zones, this classification is used by the Reproductive and Child Health Section, Ministry of Health. The reason for using zones is that each geographic area will have a relatively large number of cases and sampling error will thus be reduced. It should be noted that the zones, which are defined below, are slightly different from the zones used in the 1991-92 and 1996 TDHS reports-
A representative probability sample of 10,312 households was selected for the 2004-05 TDHS sample to provide an expected sample of 10,000 eligible women. The sample was selected in two stages. In the first stage, 475 clusters were selected from a list of enumeration areas from the 2002 Population and Housing Census. Eighteen clusters were selected in each region except Dar es Salaam, where 25 clusters were selected.
In the second stage, a complete household listing exercise was carried out between June and August 2004 within all the selected clusters. Households were then systematically selected for participation in the survey. Twenty-two households were selected from each of the clusters in all regions except for Dar es Salaam where 16 households were selected.
All women age 15-49 who were either permanent residents of the households in the 2004-05 TDHS sample or visitors present in the household on the night before the survey were eligible to be interviewed. In a subsample of one-third of all the households selected for the survey, all men age 15-49 were eligible to be interviewed if they were either permanent residents or visitors present in the household on the night before the survey.
Note: See detailed sample implementation in the APPENDIX A of the final 2004-2005 Tanzania Demographic and Health Survey report.
Response rates are important because high nonresponse may affect the reliability of the results. A total of 10,312 households were selected for the sample, of which 9,852 were found to be occupied during data collection. The shortfall was largely the result of structures that were found to be vacant or destroyed. Of the 9,852 existing households, 9,735 were successfully interviewed, yielding a household response rate of 99 percent.
In these households, 10,611 women were identified as eligible for the individual interview. Interviews were completed with 97 percent of them. Of the 2,871 eligible men identified in the subsample of households selected, 92 percent were successfully interviewed.
The principal reason for nonresponse among both eligible women and men was the failure to find them at home despite repeated visits to the household. The lower response rate for men reflects the more frequent and longer absences of men from the household.
Note: See summarized response rates in Table 1.2of the final report.
Three questionnaires were used for the 2004-05 TDHS: the Household Questionnaire, the Women’s Questionnaire, and the Men’s Questionnaire. The content of these questionnaires was based on the model questionnaires developed by the MEASURE DHS programme. To reflect relevant issues in population and health in Tanzania, the questionnaires were adapted during a series of technical meetings with various stakeholders from government ministries and agencies, nongovernmental organisations, and international donors. The final draft of the questionnaire was discussed at a large stakeholders’ meeting organised by the NBS. The adapted questionnaires were translated from English into Kiswahili and pretested during July and August 2004.
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 age, sex, education, and relationship to the head of the household. For children under 18, survival status of the parents was determined. The main purpose of the Household Questionnaire was to identify women and men who were eligible for the individual interview. The Household Questionnaire also collected information on characteristics of the household’s dwelling unit, such as the source of water, type of toilet facilities, materials used for the floor of the house, ownership of various durable goods, and ownership and use of mosquito nets.
The Household Questionnaire was also used to record height, weight, and haemoglobin measurements of women age 15-49 and children under age 6, and to record whether a household used cooking salt fortified with iodine.
The Women’s Questionnaire was used to collect information from all women age 15-49. These women were asked questions on the following topics:
The Men’s Questionnaire was administered to all men age 15-49 living in every third household in the 2004-05 TDHS sample. The Men’s Questionnaire collected much of the same information found in the Women’s Questionnaire, but was shorter because it did not contain a detailed reproductive history or questions on maternal and child health or nutrition.
Start | End |
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2004-10 | 2005-02 |
Name |
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National Bureau of Statistics |
Training of Field Staff
More than 100 people were recruited by the NBS to serve as supervisors, field editors, male and female interviewers, quality control personnel, and reserves. As in the previous surveys, the Ministry of Health was requested to secure the service of trained nurses to work as field staff. They all participated in the main interviewer training, which began on September 13, 2004 in Moshi and lasted for three weeks. Staff from the NBS and invited experts led the training, which was conducted mainly in Kiswahili and included lectures, presentations, practical demonstrations, and practice interviewing in small groups. The training included two days of field practice. The participants also received training on height and weight measurements and haemoglobin testing. Two experts from the Tanzanian Food and Nutrition Centre led those training sessions. A series of lectures was also held specifically for the group comprising supervisors, field editors, quality control personnel, and field coordinators.
Fieldwork
Data collection began on October 7, 2004 and was completed in mid-February 2005. There was a total of 14 data collection teams, each consisting of 4 female interviewers, 1 male interviewer, a supervisor, a field editor, and a driver. The field editor and supervisor were responsible for reviewing all questionnaires for quality and consistency before the team’s departure from the cluster. Fieldwork supervision was also coordinated at NBS headquarters. Four officers periodically visited teams to review their work and monitor data quality. Quality control personnel also independently reinterviewed certain households after the departure of the teams. Close contact between NBS headquarters and the data collection teams was maintained using cell phones. ORC Macro staff participated in field supervision of interviews, height and weight measurements, and haemoglobin testing.
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 2004-05 Tanzania Demographic and Health Survey (TDHS) to minimize 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 2004-05 TDHS 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 2004-05 TDHS sample is the result of a multi-stage stratified design, and, consequently, it was necessary to use more complex formulae. The computer software used to calculate sampling errors for the 2004-05 TDHS is the ISSA Sampling Error Module. This module used the Taylor linearization 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 rates.
Note: See detailed sampling error calculation in the APPENDIX B of the final report.
Data Quality Tables
Note: See these data quality tables in APPENDIX C of the final report.
Name | URL | |
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MEASURE DHS | www.measuredhs.com | archive@measuredhs.com |
Use of the dataset must be acknowledged using a citation which would include:
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.
Name | URL | |
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General Inquiries | info@measuredhs.com | www.measuredhs.com |
Data and Data Related Resources | archive@measuredhs.com | www.measuredhs.com |
DDI_WB_TZA_2004_DHS_v01_M
Name | Role |
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World Bank, Development Economics Data Group | Documentation of the study |
Version 1.0: (June 2011) Variable level metadata is not provided.
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