Abstract

The 2022 Tanzania Demographic and Health Survey and Malaria Indicator Survey (2022 TDHS-MIS) is designed to provide data for monitoring the population and health situation in Tanzania. The 2022 TDHS-MIS is the 7th Demographic and Health Survey conducted in Tanzania since 1991-92 and the 5th Malaria Indicator Survey since 2007-08. The primary objective of the survey is to provide reliable estimates of fertility levels,marriage, sexual activity, fertility preferences, awareness and use of family planning methods, breastfeeding practices, nutrition, childhood and maternal mortality, maternal and child health, malaria, other health related issues, as well as prevalence of malaria infection among children under age 5. This information is intended for use by programme managers and policymakers to evaluate and improve existing programmes

Geographic coverage

Tanzania Mainland and Zazibar

Analysis unit

The 2022 Tanzania Demographic and Health Survey and Malaria Indicator Survey (2022 TDHS-MIS) had the following unit of Analysis: Household and Individuals

Universe

The survey covered all household members (usual residents), all women aged 15-49 years resident in the household, and all children aged 0-4 years (under age 5) resident in the household.

Kind of data

Sample survey data [ssd]

Sampling procedure

The sample design for the 2022 TDHS-MIS was carried out in two stages and was intended to provide estimates for the entire country, for urban and rural areas in Tanzania Mainland, and for Zanzibar. For specific indicators such as contraceptive use, the sample design allows for estimation of indicators for each of the 31 regions-26 regions in Tanzania Mainland and 5 regions in Zanzibar. The sampling frame excluded institutional populations, such as persons in hospitals, hotels, barracks, camps, hostels, and prisons. The 2022 TDHS-MIS followed a stratified two-stage sample design. The first stage involved selection of sampling points (clusters) consisting of enumeration areas (EAs) delineated for the 2012 Tanzania Population and Housing Census (2012 PHC). The EAs were selected with a probability proportional to their size within each sampling stratum. A total of 629 clusters were selected. Among the 629 EAs, 211 were from urban areas and 418 were from rural areas. In the second stage, 26 households were selected systematically from each cluster, for a total anticipated sample size of 16,354 households for the 2022 TDHS-MIS. A household listing operation was carried out in all the selected EAs before the main survey. During the household listing operation, field staff visited each of the selected EAs to draw location maps and detailed sketch maps and to list all residential households found in each EA with addresses and the names of the heads of the households. The resulting list of households served as a sampling frame for the selection of households in the second stage. During the listing operation, field teams collected global positioning system (GPS) data-latitude, longitude, and altitude readings-to produce one GPS point per EA. To estimate geographic differentials for certain demographic indicators, Tanzania was divided into nine geographic zones. Although these zones are not official administrative areas, this classification system is also used by the Reproductive and Child Health Section of the Ministry of Health. Grouping of regions into zones allows for larger denominators and smaller sampling errors for indicators at the zonal level. The zones are as follows: Tanzania Mainland: - Western zone: Tabora, Kigoma - Northern zone: Kilimanjaro, Tanga, Arusha - Central zone: Dodoma, Singida, Manyara - Southern Highlands zone: Iringa, Njombe, Ruvuma - Southern zone: Lindi, Mtwara - Southwest Highlands zone: Mbeya, Rukwa, Katavi, Songwe - Lake zone: Kagera, Mwanza, Geita, Mara, Simiyu, Shinyanga - Eastern zone: Dar es Salaam, Pwani, Morogoro Introduction and Survey Methodology • 3 Zanzibar: - Zanzibar zone: Kaskazini Unguja, Kusini Unguja, Mjini Magharibi, Kaskazini Pemba, Kusini Pemba All women age 15-49 who were either usual residents or visitors in the household on the night before the survey interview were included in the 2022 TDHS-MIS and were eligible to be interviewed. In a subsample of half of all households selected for the survey, all men age 15-49 were eligible to be interviewed if they were either usual residents or visitors in the household on the night before the survey interview. In this subsample, children age 0-59 months, women age 15-49, and men age 15-49 were eligible for height and weight measurement. Children age 6-59 months were also eligible for anaemia and malaria testing using rapid tests. Women were eligible for anaemia testing and were asked to provide a urine sample for laboratory testing to detect the presence of iodine. In this subsample of half of households, anaemia and malaria testing were conducted using capillary blood. A subsample of approximately 20% of all households was selected for the micronutrient component. Within those households, all interviewed women age 15-49 and children age 6-59 months were eligible for venous blood collection. In 40% of the households selected for micronutrient testing, a dose of vitamin A was administered, and an additional blood sample was collected approximately 4 hours later for relative dose response testing. Questions on food fortification were asked, and samples of salt, wheat flour, maize flour, and cooking oil were collected from the household. Blood specimens and food samples were collected, processed, and sent to TFNC for storage and analysis. Drops of the venous blood collected from women and children in the field were tested on-the-spot for anaemia and malaria. Haematocrit was measured in venous blood collected from women, and all blood samples were processed on the same day they were collected to prepare them for frozen storage until the start of laboratory testing. A range of micronutrient laboratory analyses was carried out by TFNC. The results for all tests conducted in the 20% of households included in the micronutrient component will be published in a separate report. Results of the anaemia testing for children and women in this micronutrient subsample using venous blood are published in this report and will be included in the separate micronutrient report as well.

Mode of data collection

Computer Assisted Personal Interview [capi]

Research instrument

Five questionnaires were used for the 2022 TDHS-MIS: the Household Questionnaire, the Woman’s Questionnaire, the Man’s Questionnaire, the Biomarker Questionnaire, and the Micronutrient Questionnaire. The questionnaires, based on The DHS Program’s Model Questionnaires, were adapted to reflect the population and health issues relevant to Tanzania. In addition, a self-administered Fieldworker’s Questionnaire collected information about the survey’s fieldworkers. The Household Questionnaire was used to list all the usual members and visitors in the selected households. Basic demographic information was collected on characteristics of each person listed, including age, sex, marital status, education, and relationship to the head of the household. Parents’ survival status was determined for children under age 18. The data on age and sex of household members obtained from the Household Questionnaire were used to identify women and men who were eligible for individual interviews. The Household Questionnaire also collected information on characteristics of the household’s dwelling unit, such as source of drinking water, type of toilet facilities, materials used for the floor of the dwelling unit, ownership of various durable goods, and ownership and use of mosquito nets. Questions were also asked about the disability status of household members age 5 or above. The Household Questionnaire also collected information on the results of iodine tests conducted on the salt consumed by households. The Woman’s Questionnaire was used to collect information from all eligible women age 15–49. These women were asked questions on the following topics: - Background characteristics (age, education, media exposure, etc.) - Birth history and childhood mortality - Knowledge and use of family planning methods - Fertility preferences, antenatal, delivery, and postnatal care - Breastfeeding and infant feeding practices - Vaccinations and childhood illnesses - Marriage and sexual activity - Women’s work and husband’s background characteristics - Other health issues - Adult mortality, including maternal mortality - Female genital cutting - Early childhood development - Malaria - Domestic violence The Man’s Questionnaire was administered to all men age 15–49 in the subsample of households selected for the men’s survey. The Man’s Questionnaire collected much of the same information found in the Woman’s Questionnaire, but it was shorter because it did not contain a detailed reproductive history or questions on maternal and child health. The Biomarker Questionnaire was used to record anthropometric (height and weight) measurements for children under age 5 and women and men age 15–49; to record anaemia test results for children age 6–59 months and women age 15–49; to record malaria rapid test results for children age 6–59 months; and to document responses to requests to women age 15–49 to collect urine samples for laboratory testing of urinary iodine. The samples were to be tested later for iodine at the TFNC laboratory. A Micronutrient Questionnaire was used to record anthropometric measurements, anaemia and malaria test results, and haematocrit results for women and to document the outcome of

Abstract

The Tanzania Demographic and Health Survey (TDHS) is a national sample survey of women of reproductive ages (15-49) and men aged 15 to 60. The survey was designed to collect data on socioeconomic characteristics, marriage patterns, birth history, breastfeeding, use of contraception, immunisation of children, accessibility to health and family planning services, treatment of children during times of illness, and the nutritional status of children and their mothers.

The primary objectives of the TDHS were to: - Collect data for the evaluation of family planning and health programmes, - Determine the contraceptive prevalence rate, which will help in the design of future national family planning programmes, and - Assess the demographic situation of the country.

Geographic coverage

The Tanzania Demographic and Health Survey (TDHS) is a national sample survey. This sample should allow for separate analyses in urban and rural areas, and for estimation of contraceptive use in each of the 20 regions located on the mainland and in Zanzibar.

Analysis unit

Households, individuals

Universe

Men and women between the ages of 15-49, children under 5

Kind of data

Sample survey data

Sampling procedure

The principal objective of the Tanzania Demographic and Health Survey (TDHS) was to collect data on fertility, family planning, and health of the people. This survey involved randomly selected women aged 15-49 and men aged 15-60 in selected households.

Before the sampling frame was developed, two possibilities for the TDHS sample design were considered: - The 1988 Population census list of Enumeration Areas (EAs) - The National Master Sample for Tanzania created in 1986 (NMS).

The NMS was intended mainly for agricultural purposes and, at that time, only for rural areas. The NMS was based on the 1978 Census information while the urban frame was still being worked upon. Therefore, it was decided that the TDHS sample design would use the 1988 Census information as the basic sampling frame. Since the TDHS sample was to be clustered, it was necessary to have sampling units of manageable and fairly uniform size and with very well defined boundaries. The 1988 Census frame provided the list of enumeration area units (EAs) that had well defined boundaries and manageable uniform size. Therefore, EAs were used as primary sampling units (PSUs).

The target of the TDHS sample was about 7850 women age 15-49 with completed interviews. This sample should allow for separate analyses in urban and rural areas, and for estimation of contraceptive use in each of the 20 regions located on the mainland and in Zanzibar. Estimates for large domains (by combination of a group of regions) were also taken into consideration.

The TDHS used a three-stage sample. The frame was stratified by urban and rural areas. The primary sampling units in the TDHS survey were the wards/branches. The design involved the target of 350 completed interviews for each of 19 regions on the mainland and 500 in each of Dar es Salaam and Zanzibar.

In the first stage, the wards/branches were systematically selected with probability proportional to size (according to 1988 census information). In a second sampling stage, two EAs per selected rural ward/branch and one EA per selected urban ward/branch were chosen with probability proportional to size (also according to 1988 census information). In total, 357 EAs were selected for the TDHS, 95 in the urban area and 262 in the rural. A new listing of households was made shortly before the TDHS fieldwork by special teams including a total of 14 field workers. These teams visited the selected EAs all over the country to list the names of the heads of the households and obtain the population composition of each household (total number of persons in the household). In urban areas, the address of the dwelling was also recorded in order to make it easy to identify the household during the main survey. A fixed number of 30 households in each rural EA and 20 in each urban EA were selected.

About 9560 households were needed to achieve the required sample size, assuming 80 percent overall household completion rate.

See detailed sampling information in the APPENDIX B of the final 1991-1992 Tanzania Demographic and Health Survey report.

Mode of data collection

Face-to-face

Research instrument

The household, female, and male questionnaires were designed by following the Model Questionnaire "B" which is for low contraceptive prevalence countries. Some adaptations were made to suit the Tanzania situation, but the core questions were not changed. The original questionnaire was prepared in English and later translated into Kiswahili, the language that is widely spoken in the country. There are parts in the country where people are not very conversant with Kiswahili and would find it difficult to respond in Kiswahili but would understand when they are asked anything. The translated document was given to another translator to translate it back into English and comparisons were made to determine the differences.

PRETEST

A pretest to assess the viability of the survey instruments, particularly the questionnaires and the field organization, was carried out in Iringa Rural District, Iringa Region. It covered 16 enumeration areas with a total of 320 households. The pretest, which took a month to complete, was carded out in November/December, 1990, and covered both rural and urban EAs.

The pretest training took two weeks and consisted of classroom training and field practice in neighborhood areas. In all, 14 newly recruited interviewers and the Census staff were involved. The Census staffs who were to be transformed into the TDHS team handled the training for both the fieldwork management and the questionnaire. During the later fieldwork, they supervised the field exercise.

During the fieldwork, the administrative structure of the CCM Party, which involved the Party Branch Offices and the ten-cell leadership, were utilized in an effort to secure the maximum confidence and cooperation of the people in the areas where the team was working. At the end of the fieldwork, the interviewers and the supervisory team returned to the head office in Dares Salaam for debriefing and discussion of their field experiences, particularly those related to the questionnaires and the logistic problems that were encountered. All these experiences were used to improve upon the final version of the questionnaires and the overall logistic arrangements.

Response rate

Out of the 9282 households selected for interview, 8561 households could be located and 8327 were actually interviewed. The shortfall between selected and interviewed households was largely due to the fact that many dwellings were either vacant or destroyed or no competent respondents were present at the time of the interview. A total of 9647 eligible women (i.e., women age 15-49 who spent the night before the interview in a sampled household) were identified for interview, and 9238 women were actually interviewed (96 percent response rate). The main reason for non-interview was absence from the home or incapacitation.

The Tanzania DHS male survey covered men aged between 15 and 60 years who were living in selected households (every fourth household of the female survey). The results of the survey show that 2392 eligible men were identified and 2114 men were interviewed (88 percent response rate). Men were generally not interviewed because they were either incapacitated or not at home during the time of the survey.

Sampling error estimates

The results from sample surveys are affected by two types of errors, non-sampling error and sampling error. Non-sampling error is due to mistakes made in carrying out field activities, such as failure to locate and interview the correct household, errors in the way the questions are asked, misunderstanding on the part of either the interviewer or the respondent, and data entry errors. Although efforts were made to minimize this type of error during the design and implementation of the TDHS, non-sampling errors are impossible to avoid and difficult to evaluate statistically.

Sampling errors, on the other hand, can be measured statistically. The sample of women selected in the TDHS is only one of many samples that could have been selected from the same population, using the same design and expected size. Each one would have yielded results that differed somewhat from the actual sample selected. The sampling error is a measure of the variability between all possible samples; although it is not known exactly, it can be estimated from the survey results.

Sampling error is usually measured in terms of standard error of 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 one can be reasonably assured that, apart from non-sampling errors, the true value of the variable for the whole population falls. For example, for any given statistic calculated from a sample survey, the value of that same statistic as measured in 95 percent of all possible samples with the same design (and expected size) will fall within a range of plus or minus two times the standard error of that statistic.

If the sample of women had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the Tanzania DHS sample designs depended on stratification, stages, and clusters. Consequently, it was necessary to utilize more complex formulas. The computer package

DHS - Tanzania

Abstract

The principal objective of the 2010 TDHS is to collect data on household characteristics, fertility levels and preferences, awareness and use of family planning methods, childhood and adult mortality, maternal and child health, breastfeeding practices, antenatal care, childhood immunisation and diseases, nutritional status of young children and women, malaria prevention and treatment, women’s status, female circumcision, sexual activity, knowledge and behaviour regarding HIV/AIDS, and prevalence of domestic violence.

Geographic coverage

Tanzania Mainland and Zanzibar

Analysis unit

Household and Individual (Women and Men)

Universe

The survey covered all de jure household members (usual residents), all women aged 15-49 years resident in the household, and all children under age 5 resident in the household.

Kind of data

Sample survey data [ssd]

Sampling procedure

The 2010 TDHS sample was designed to provide estimates for the entire country, for urban and rural areas in the Mainland, and for Zanzibar. For specific indicators such as contraceptive use, the sample design allowed the estimation of indicators for each of the then 26 regions.

To estimate geographic differentials for certain demographic indicators, the regions of mainland Tanzania were collapsed into seven geographic zones. Although these are not official administrative zones, this classification is used by the Reproductive and Child Health Section of the MoHSW. Zones were used in each geographic area in order to have a relatively large number of cases and a reduced sampling error. It should be noted that the zones, which are defined below, differ slightly from the zones used in the 1991-92 and 1996 TDHS reports but are the same as those in the 2004-05 TDHS and the 2007-08 THMIS.

Western: Tabora, Shinyanga, Kigoma Northern: Kilimanjaro, Tanga, Arusha, Manyara Central: Dodoma, Singida Southern Highlands: Mbeya, Iringa, Rukwa Lake: Kagera, Mwanza, Mara Eastern: Dar es Salaam, Pwani, Morogoro Southern: Lindi, Mtwara, Ruvuma Zanzibar: Unguja North, Unguja South, Town West, Pemba North, Pemba South

A representative probability sample of 10,300 households was selected for the 2010 TDHS. The sample was selected in two stages. In the first stage, 475 clusters were selected from a list of enumeration areas in the 2002 Population and Housing Census. Twenty-five sample points were selected in Dar es Salaam, and 18 were selected in each of the other twenty regions in mainland Tanzania. In Zanzibar, 18 clusters were selected in each region for a total of 90 sample points.

In the second stage, a complete household listing was carried out in all selected clusters between July and August 2009. 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 in the households included in the 2010 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.

Mode of data collection

Face-to-face [f2f]

Research instrument

Three questionnaires were used for the 2010 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. Contributions were solicited from various stakeholders representing government ministries and agencies, nongovernmental organisations, and international donors. The final drafts of the questionnaires were discussed at a stakeholders’ meeting organised by the NBS. The adapted questionnaires were translated from English into Kiswahili and pretested from 23 July 2009 to 5 August 2009.

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 age 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. Another use of the Household Questionnaire was to identify the woman who was eligible to be interviewed with the domestic violence module.

The Household Questionnaire was also used to record height, weight, and haemoglobin measurements of women age 15-49 and children under age 5, household use of cooking salt fortified with iodine, response to requests for blood samples to measure vitamin A and iron in women and children, and whether salt and urine samples were provided.

The Women’s Questionnaire was used to collect information from all women age 15-49. These women were asked questions on the following topics: • Background characteristics (e.g., education, residential history, media exposure) • Birth history and childhood mortality • Pregnancy, delivery, and postnatal care • Knowledge and use of family planning methods • Infant feeding practices, including patterns of breastfeeding • Fertility preferences • Episodes of childhood illness and responses to illness, with a focus on treatment of fevers in the two weeks prior to the survey • Vaccinations and childhood illnesses • Marriage and sexual activity • Husband’s background and women’s work status • Knowledge, attitudes, and behaviour related to HIV/AIDS and other sexually transmitted infections (STIs) • Domestic violence • Female genital cutting • Adult mortality, including maternal mortality • Fistula of the reproductive and urinary tracts • Other health issues, including knowledge of tuberculosis and medical injections

The Men’s Questionnaire was administered to all men age 15-49 living in every third household in the 2010 TDHS sample. The Men’s Questionnaire collected much of the same information as the Women’s Questionnaire, but it was shorter because it did not contain a detailed reproductive history, questions on maternal and child health or nutrition, questions about fistula, or questions about siblings for the calculation of maternal mortality.

Cleaning operations

Field teams were advised of problems detected during the data entry to improve performance with the use of field check tables. The process of office editing and data processing was initiated on 25 January 2010 and completed on 15 June 2010.

The DBS, urine, and salt samples received from the field were logged in at NBS, checked, and delivered to TFNC to be tested. The processing of DBS samples for the vitamin A testing was handled by three laboratory technicians, while anaemia testing was handled by three laboratory technicians, and iodine testing was done by four laboratory technicians. The samples were logged into the CSPro Test Tracking System (CHTTS) database, and each was given a laboratory number.

Response rate

A total of 10,300 households were selected for the sample, of which 9,741 were found to be occupied during data collection. The shortfall occurred mainly because structures were vacant or destroyed. Of the 9,741 existing households, 9,623 were successfully interviewed, yielding a household response rate of 99 percent.

In the interviewed households, 10,522 women were identified for individual interview; complete interviews were conducted with 10,139 women, yielding a response rate of 96 percent. Of the 2,770 eligible men identified in the subsample of households selected, 91 percent were successfully interviewed.

The principal reason for nonresponse among 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 households.

Sampling error estimates

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.

However, the 2010 TDHS sample is the result of a multi-stage stratified design, and, consequently, it was necessary to use more complex formulas. The computer software used to calculate sampling errors for the 2010 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

Abstract

The primary objective of the 2015-16 Tanzania Demographic and Health Survey and Malaria Indicator Survey (TDHS-MIS) is to provide up-to-date estimates of basic demographic and health indicators. This survey collected information on fertility levels, marriage, sexual activity, fertility preferences, awareness and use of family planning methods, breastfeeding practices, nutrition, childhood and maternal mortality, maternal and child health, malaria, and other health-related issues. In addition, the 2015-16 TDHS-MIS provided estimates of anaemia prevalence among children age 6-59 months and women age 15-49 years, estimates of malaria prevalence among children age 6-59 months, and estimates of iodine concentration in household salt and women’s urine.

The information collected through the 2015-16 TDHS-MIS is intended to assist policy makers and programme managers in evaluating and designing programmes and strategies to improve the health of the country’s population.

Geographic coverage

National

Analysis unit

• Household
• Children age 0-5
• Women age 15-49
• Men age 15-59

Kind of data

Sample survey data [ssd]

Sampling procedure

Sample Design The sample design for the 2015-16 TDHS-MIS was done in two stages and was intended to provide estimates for the entire country, for urban and rural areas in Tanzania Mainland, and for Zanzibar. For specific indicators such as contraceptive use, the sample design allowed the estimation of indicators for each of the 30 regions (25 regions from Tanzania Mainland and 5 regions from Zanzibar). The first stage involved selecting sample points (clusters), consisting of enumeration areas (EAs) delineated for the 2012 Tanzania Population and Housing Census. A total of 608 clusters were selected.

In the second stage, a systematic selection of households was involved. A complete households listing was carried out for all 608 selected clusters prior to the fieldwork. From the list, 22 households were then systematically selected from each cluster, yielding a representative probability sample of 13,376 households for the 2015-16 TDHS-MIS. To estimate geographic differentials for certain demographic indicators, Tanzania was divided into nine geographic zones. Although these zones are not official administrative areas, this classification system is also used by the Reproductive and Child Health Section of the MoHCDGEC. Grouping the regions into zones allowed a relatively large number of people in the denominator and a reduced sampling error. Note that the zones, defined below, differ slightly from the zones used in previous DHS surveys. Therefore, comparisons across the zones and from survey to survey should be made with caution. The zones are as follows: Western Zone: Tabora, Kigoma Northern Zone: Kilimanjaro, Tanga, Arusha Central Zone: Dodoma, Singida, Manyara Southern Highlands Zone: Iringa, Njombe, Ruvuma Southern Zone: Lindi, Mtwara South West Highlands Zone: Mbeya, Rukwa, Katavi Lake Zone: Kagera, Mwanza, Geita, Mara, Simiyu, Shinyanga Eastern Zone: Dar es Salaam, Pwani, Morogoro Zanzibar: Kaskazini Unguja, Kusini Unguja, Mjini Magharibi, Kaskazini Pemba, Kusini Pemba

All women age 15-49 who were either usual residents or visitors in the household on the night before the survey were included in the 2015-16 TDHS-MIS and 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 usual residents or visitors in the household on the night before the survey. In all households, with the parent's or guardian's consent, children age 6-59 months were tested for anaemia and malaria. All interviewed women were tested for anaemia. In the households selected for interviews with men, interviewed women were asked to provide a urine sample and a sample of household salt for laboratory testing to detect the presence of iodine.

For further details of sample design and implementation, see Appendix A of the final report.

Mode of data collection

Face-to-face [f2f]

Research instrument

Four questionnaires were used for the 2015-16 TDHS-MIS: the Household Questionnaire, the Woman’s Questionnaire, the Man’s Questionnaire, and the Biomarker Questionnaire. These questionnaires were based on the DHS Program’s standard Demographic and Health Survey (DHS) questionnaires. They were adapted to reflect the population and health issues relevant to Tanzania. Inputs were solicited from various stakeholders representing government ministries, departments, and agencies; non-governmental organizations; and development partners. After the preparation of the definitive questionnaires in English, the questionnaires were translated into Kiswahili.

Cleaning operations

In the 2015-16 TDHS-MIS the first data entry was done concurrently with data collection in the field. After the paper questionnaires were completed, edited, and checked by both the field editor and the supervisor, the data was entered into a tablet equipped with a data entry programme. This was done by the editor. Completed questionnaires were then sent to NBS headquarters, where they were entered for the second time and edited by data processing personnel who were given special training for this task. ICF International provided technical assistance during the entire data processing period.

Processing the data concurrently with data collection allowed for regular monitoring of team performance and data quality. Field check tables were generated regularly during data processing to check various data quality parameters. As a result, feedback was given on a regular basis, encouraging teams to continue in areas of good performance and to correct areas in need of improvement. Feedback was individually tailored to each team. Data entry, which included 100% double entry to minimise keying errors, and data editing, were completed on March 21, 2016. Data cleaning and finalization were completed on April 22, 2016.

Response rate

A total of 13,360 households were selected for the survey, of which 12,767 were occupied. Of the occupied households, 12,563 were successfully interviewed, yielding a response rate of 98%.

In the interviewed households, 13,634 eligible women were identified for individual interviews; interviews were completed with 13,266 women, yielding a response rate of 97%. In the subsample of households selected for the male survey, 3,822 eligible men were identified and 3,514 were successfully interviewed, yielding a response rate of 92%. There is little variation in household response rates between rural and urban residences.

Sampling error estimates

The estimates from a sample survey are affected by two types of errors: (1) nonsampling errors, and (2) sampling errors. Nonsampling 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 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 2015 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 2015 TDHS is only one of many samples that could have been selected from the same population, using the same design and identical 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 2015 TDHS sample is the result of a multi-stage stratified design, and, consequently, it was necessary to use more complex formulas. The computer software used to calculate sampling errors for the 2015 TDHS is a SAS program. This program used the Taylor linearization method for variance estimation for survey estimates that are means or proportions. The Jackknife repeated replication method was used for variance estimation of more complex statistics such as fertility and mortality rates.

The Taylor linearization method treats any percentage or average as a ratio estimate, r = y/x, where y represents the total sample value for variable y, and x represents the total number of cases in the group or subgroup under consideration.

For further details on sampling error calculations see Appendix B of the final report.

Data appraisal

Data quality tables were produced to review the quality of the data: - Household age distribution - Age distribution of eligible and interviewed women - Age distribution of eligible and

The 2004-05 Tanzania DHS is part of the worldwide Demographic and Health Surveys (DHS) programme which assists countries in the collection of data to monitor and evaluate population, health, and nutrition programmes.

The principal objective of the 2004-05 TDHS was to collect data on household characteristics, fertility levels and preferences, awareness and use of family planning methods, childhood mortality, maternal and child health, breastfeeding practices, antenatal care, childhood immunisation and diseases, nutritional status of young children and women, malaria prevention and treatment, women’s status, female circumcision, sexual activity, and knowledge and behaviour regarding HIV/AIDS and other STIs.

Abstract

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 general objectives of the 1996 TDHS are to: - Provide national-level data that will allow the calculation of demographic rates, particularly fertility and childhood mortality rates - Analyze the direct and indirect factors which determine the level and trends of fertility - Measure the level of contraceptive knowledge and practice (of both women and men) by method, by urban-rural residence, and by region - Collect reliable data on maternal and child health indicators; immunization, prevalence, and treatment of diarrhea and other diseases among children under age five; antenatal visits; assistance at delivery; and breastfeeding - Assess the nutritional status of children under age five and their mothers by means of anthropometric measurements (weight and height), and child feeding practices - Assess among women and men the prevailing level of specific knowledge and attitudes regarding AIDS and evaluate patterns of recent behavior regarding condom use - Measure maternal mortality and collect data on female circumcision.

Geographic coverage

The survey was designed to provide estimates (based on the results of the Woman's Questionnaire) for the whole country, for urban and rural areas in the country, and groups of regions (zones). In addition, the sample provides certain estimates for each of the 20 regions in the mainland and 2 subgroups in Zanzibar: Pemba Island and Ungaja.

In most regions, one in every four households was selected for the men's survey, and in six regions (Dares Salaam, Dodoma, Iringa, Kilimanjaro, Morogoro, and Shinyanga), men in every second household were selected for the interview. The sample of men was designed to provide estimates for the country as a whole and for urban and rural areas.

Analysis unit

Households, individuals

Universe

Men and women between the ages of 15-49, children under 5

Kind of data

Sample survey data

Sampling procedure

The TDHS sample was a three-stage design consisting of the same 357 enumeration areas (EAs) that were used in the 1991-92 TDHS (262 EAs in rural and 95 EAs in urban areas). The selection of EAs was made in two stages: first, wards/branches and then EAs within wards/branches were selected. Lists of all households were prepared for the selected EAs and, at the third sampling stage; households were selected from these lists. The TDHS was designed to provide estimates (based on the results of the Woman's Questionnaire) for the whole country, for urban and rural areas in the country, and groups of regions (zones). In addition, the sample will provide certain estimates for each of the 20 regions in the mainland and 2 subgroups in Zanzibar: Pemba Island and Ungaja. In most regions, one in every four households was selected for the men's survey, and in six regions (Dares Salaam, Dodoma, Iringa, Kilimanjaro, Morogoro, and Shinyanga), men in every second household were selected for the interview. The sample of men was designed to provide estimates for the country as a whole and for urban and rural areas.

Unlike most other DHS surveys, households in Tanzania were selected from the household listing for each ward (or branch) on the basis of contiguity, beginning with a randomly selected start number. This selection process was used to minimize the difficulty encountered in moving from one selected household to another given the scattered nature of households.

See detailed sample design information in the APPENDIX A of the final 1996 Tanzania Demographic and Health Survey report.

Mode of data collection

Face-to-face

Research instrument

Three types of questionnaires were used during the survey. The Household Questionnaire was used to list the names of the household members and certain individual characteristics of all usual members of the household and visitors who had spent the previous night in the household. Certain basic information was collected on characteristics of each person listed, including relationship, age, sex, education, and place of residence. Furthermore, the Household Questionnaire collected information on characteristics relating to the household. These included the source of water, type of toilet facilities, materials used for the floor of the house, and ownership of various durable goods. However, the main purpose of the Household Questionnaire was to identify women and men who were eligible for the individual interview.

The Female Questionnaire was used to collect information from eligible women age 15-49. The topics covered in this questionnaire included the following: - Background characteristics of the woman including age, education, residential history - Reproductive history - Knowledge and use of family planning methods - Fertility preferences and attitudes about family planning - Antenatal and delivery care - Breastfeeding and weaning practices - Vaccinations and health status of children under age five - Marriage and sexual activity - Husband's occupation and education - Woman's employment, occupation, and earnings - Awareness and behavior regarding AIDS and other sexually transmitted diseases - Maternal mortality - Female circumcision - Height and weight of children under five years and their mothers.

The Male Questionnaire was used to collect information from a subsample of men age 15-59, namely, those living in every fourth household except in Dares Salaam, Dodoma, Kilimanjaro, Morogoro, Shinyanga, and Iringa regions where every second household was selected for the male interview. The Male Questionnaire collected much of the same information found in the Women's Questionnaire, but was shorter because it did not contain questions on reproductive history and maternal and child health. All questionnaires were translated and printed in Kiswahili.

Before the design of the questionnaires could be finalized, a pretest was done in May-June, 1996 to assess the viability of the questions, the flow and logical sequence of the skip pattern, and the field organization. It covered an area outside Dares Salaam and took about a week to complete. Modifications to the questionnaires were then made based on lessons drawn from the exercise.

Response rate

In all, 8,900 households were selected, out of which 8,141 were occupied. Of the households found, 7,969 were interviewed, representing a response rate of 98 percent. The shortfall between the selected and the interviewed households was largely because many dwellings were either vacant or no competent respondents were present at the time of the visit.

In the interviewed households, 8,501 eligible women (i.e. women age 15- 49) were identified for the individual interview, and 8,120 women were actually interviewed, yielding a response rate of 96 percent. In the subsample of households selected for the male interview, 2,658 eligible men (i.e., men age 15-59) were identified, 2,256 were interviewed, representing a response rate of 85 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 rates among men than women were due to the more frequent and longer absences of men.

The response rates are lower in urban areas. One-member households are more common in urban areas and are more difficult to interview because they keep their houses locked up most of the time. In urban settings, neighbors often do not know the whereabouts of such people.

Sampling error estimates

The estimates from a sample survey are affected by two types of errors: non-sampling errors, and 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 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 1996 TDHS to minimize this type of error, non-sampling 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 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, straightforward formulae for calculating sampling errors could have been used. However, the TDHS sample is the result of a two-stage stratified design, and, consequently, it was necessary to use more complex formulae.

Analysis unit

Woman, Birth, Child, Birth, Man, Household Member

Universe

Women age 15-49, Births, Children age 0-4, Men age 15-59, All persons

Kind of data

Demographic and Household Survey [hh/dhs]

Sampling procedure

MICRODATA SOURCE: National Bureau of Statistics [Tanzania] and Macro International Inc.

SAMPLE UNIT: Woman SAMPLE SIZE: 4029

SAMPLE UNIT: Birth SAMPLE SIZE: 11952

SAMPLE UNIT: Child SAMPLE SIZE: 3215

SAMPLE UNIT: Man SAMPLE SIZE: 3542

SAMPLE UNIT: Member SAMPLE SIZE: 19255

Mode of data collection

Face-to-face [f2f]

Tanzania Demographic and Health Survey 2010 is the eighth round survey to be conducted in Tanzania. 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), the 2003-04 Tanzania HIV/AIDS Indicator Survey (THIS), TDHS 2004-2005 and the 2007-08 Tanzania HIV/AIDS and Malaria Indicator Survey (THMIS).

The 2004-2005 Tanzania Demographic and Health Survey (DHS) is the sixth in a series of national survey conducted in Tanzania to measure level, patterns and trends in demographics and health indicators. The first 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)

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.

Not specified

This collection consists of geospatial data layers and summary data at the country and country sub-division levels that are part of USAID's Demographic Health Survey Spatial Data Repository. This collection includes geographically-linked health and demographic data from the DHS Program and the U.S. Census Bureau for mapping in a geographic information system (GIS). The data includes indicators related to: fertility, family planning, maternal and child health, gender, HIV/AIDS, literacy, malaria, nutrition, and sanitation. Each set of files is associated with a specific health survey for a given year for over 90 different countries that were part of the following surveys:Demographic Health Survey (DHS)Malaria Indicator Survey (MIS)Service Provisions Assessment (SPA)Other qualitative surveys (OTH)Individual files are named with identifiers that indicate: country, survey year, survey, and in some cases the name of a variable or indicator. A list of the two-letter country codes is included in a CSV file.Datasets are subdivided into the following folders:Survey boundaries: polygon shapefiles of administrative subdivision boundaries for countries used in specific surveys. Indicator data: polygon shapefiles and geodatabases of countries and subdivisions with 25 of the most common health indicators collected in the DHS. Estimates generated from survey data.Modeled surfaces: geospatial raster files that represent gridded population and health indicators generated from survey data, for several countries.Geospatial covariates: CSV files that link survey cluster locations to ancillary data (known as covariates) that contain data on topics including population, climate, and environmental factors.Population estimates: spreadsheets and polygon shapefiles for countries and subdivisions with 5-year age/sex group population estimates and projections for 2000-2020 from the US Census Bureau, for designated countries in the PEPFAR program.Workshop materials: a tutorial with sample data for learning how to map health data using DHS SDR datasets with QGIS. Documentation that is specific to each dataset is included in the subfolders, and a methodological summary for all of the datasets is included in the root folder as an HTML file. File-level metadata is available for most files. Countries for which data included in the repository include: Afghanistan, Albania, Angola, Armenia, Azerbaijan, Bangladesh, Benin, Bolivia, Botswana, Brazil, Burkina Faso, Burundi, Cape Verde, Cambodia, Cameroon, Central African Republic, Chad, Colombia, Comoros, Congo, Congo (Democratic Republic of the), Cote d'Ivoire, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, Eswatini (Swaziland), Ethiopia, Gabon, Gambia, Ghana, Guatemala, Guinea, Guyana, Haiti, Honduras, India, Indonesia, Jordan, Kazakhstan, Kenya, Kyrgyzstan, Lesotho, Liberia, Madagascar, Malawi, Maldives, Mali, Mauritania, Mexico, Moldova, Morocco, Mozambique, Myanmar, Namibia, Nepal, Nicaragua, Niger, Nigeria, Pakistan, Papua New Guinea, Paraguay, Peru, Philippines, Russia, Rwanda, Samoa, Sao Tome and Principe, Senegal, Sierra Leone, South Africa, Sri Lanka, Sudan, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Uganda, Ukraine, Uzbekistan, Viet Nam, Yemen, Zambia, Zimbabwe

This collection consists of summary data for countries, country subdivisions, and demographic categories that were generated from USAID's Demographic Health Survey (DHS). The indicators are population-level estimates that were generated from sample surveys that were conducted in over 90 low and middle income countries at various points over several decades. Almost 2,000 indicators capture information related to: fertility, family planning, maternal and child health, gender, HIV/AIDS, literacy, malaria, nutrition, and sanitation.Each set of files is associated with a specific health survey for a given year and country. The surveys include:AIDS Indicator Survey (AIS)Demographic Health Survey (DHS)Malaria Indicator Survey (MIS)Service Provisions Assessment (SPA)Other qualitative surveys (OTH)The top-level folder includes a list of country codes and field names used in all of the data files, and a file list with a record count. The data was extracted from the DHS program's API, and is structured as follows:Datasets are organized in folders that are named with a two-letter country code, survey name, and year.Each survey has three sets of files: a National file with country-level records, a Subnational file with country subdivision-level records, and a Background file with categorical records (such as urban / rural, education level, income level, etc.)Each set of files comes in two formats: a long-format JSON file with key-value pairs of labels and values, and a wide-format CSV file where labels have been pivoted to column headings.A _CODEBOOKS folder contains CSV, JSON, and HTML files that describe the variables and all coded values, and PDF documentation for the overall DHS statistics program.Reports associated with a specific survey that were available via the API are stored in the survey folder with the data.A PUBS_NODATA folder includes reports that were available via the API, but that did not have machine-readable data associated with them.Countries for which data was included in the indicators API include:Afghanistan, Albania, Angola, Armenia, Azerbaijan, Bangladesh, Benin, Bolivia, Botswana, Brazil, Burkina Faso, Burundi, Cape Verde, Cambodia, Cameroon, Central African Republic, Chad, Colombia, Comoros, Congo, Congo (Democratic Republic of the), Cote d'Ivoire, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, Eswatini (Swaziland), Ethiopia, Gabon, Gambia, Ghana, Guatemala, Guinea, Guyana, Haiti, Honduras, India, Indonesia, Jordan, Kazakhstan, Kenya, Kyrgyzstan, Laos, Lesotho, Liberia, Madagascar, Malawi, Maldives, Mali, Mauritania, Mexico, Moldova, Morocco, Mozambique, Myanmar, Namibia, Nepal, Nicaragua, Niger, Nigeria, Pakistan, Papua New Guinea, Paraguay, Peru, Philippines, Rwanda, Samoa, Sao Tome and Principe, Senegal, Sierra Leone, South Africa, Sri Lanka, Sudan, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Uganda, Ukraine, Uzbekistan, Viet Nam, Yemen, Zambia, Zimbabwe

Abstract

The Tanzania Demographic and Health Survey (TDHS) is a national sample survey of women of reproductive ages (15-49) and men aged 15 to 60. The survey was designed to collect data on socioeconomic characteristics, marriage patterns, birth history, breastfeeding, use of contraception, immunisation of children, accessibility to health and family planning services, treatment of children during times of illness, and the nutritional status of children and their mothers.

The primary objectives of the TDHS were to: - Collect data for the evaluation of family planning and health programmes, - Determine the contraceptive prevalence rate, which will help in the design of future national family planning programmes, and - Assess the demographic situation of the country.

Geographic coverage

The Tanzania Demographic and Health Survey (TDHS) is a national sample survey. This sample should allow for separate analyses in urban and rural areas, and for estimation of contraceptive use in each of the 20 regions located on the mainland and in Zanzibar.

Analysis unit

• Households
• Children under five years
• Women age 15-49
• Men age 15-60

Kind of data

Sample survey data

Sampling procedure

The principal objective of the Tanzania Demographic and Health Survey (TDHS) was to collect data on fertility, family planning, and health of the people. This survey involved randomly selected women aged 15-49 and men aged 15-60 in selected households.

Before the sampling frame was developed, two possibilities for the TDHS sample design were considered: - The 1988 Population census list of Enumeration Areas (EAs) - The National Master Sample for Tanzania created in 1986 (NMS).

The NMS was intended mainly for agricultural purposes and, at that time, only for rural areas. The NMS was based on the 1978 Census information while the urban frame was still being worked upon. Therefore, it was decided that the TDHS sample design would use the 1988 Census information as the basic sampling frame. Since the TDHS sample was to be clustered, it was necessary to have sampling units of manageable and fairly uniform size and with very well defined boundaries. The 1988 Census frame provided the list of enumeration area units (EAs) that had well defined boundaries and manageable uniform size. Therefore, EAs were used as primary sampling units (PSUs).

The target of the TDHS sample was about 7850 women age 15-49 with completed interviews. This sample should allow for separate analyses in urban and rural areas, and for estimation of contraceptive use in each of the 20 regions located on the mainland and in Zanzibar. Estimates for large domains (by combination of a group of regions) were also taken into consideration.

The TDHS used a three-stage sample. The frame was stratified by urban and rural areas. The primary sampling units in the TDHS survey were the wards/branches. The design involved the target of 350 completed interviews for each of 19 regions on the mainland and 500 in each of Dar es Salaam and Zanzibar.

In the first stage, the wards/branches were systematically selected with probability proportional to size (according to 1988 census information). In a second sampling stage, two EAs per selected rural ward/branch and one EA per selected urban ward/branch were chosen with probability proportional to size (also according to 1988 census information). In total, 357 EAs were selected for the TDHS, 95 in the urban area and 262 in the rural. A new listing of households was made shortly before the TDHS fieldwork by special teams including a total of 14 field workers. These teams visited the selected EAs all over the country to list the names of the heads of the households and obtain the population composition of each household (total number of persons in the household). In urban areas, the address of the dwelling was also recorded in order to make it easy to identify the household during the main survey. A fixed number of 30 households in each rural EA and 20 in each urban EA were selected.

About 9560 households were needed to achieve the required sample size, assuming 80 percent overall household completion rate.

See detailed sampling information in the APPENDIX B of the final 1991-1992 Tanzania Demographic and Health Survey report.

Mode of data collection

Face-to-face

Research instrument

The household, female, and male questionnaires were designed by following the Model Questionnaire "B" which is for low contraceptive prevalence countries. Some adaptations were made to suit the Tanzania situation, but the core questions were not changed. The original questionnaire was prepared in English and later translated into Kiswahili, the language that is widely spoken in the country. There are parts in the country where people are not very conversant with Kiswahili and would find it difficult to respond in Kiswahili but would understand when they are asked anything. The translated document was given to another translator to translate it back into English and comparisons were made to determine the differences.

PRETEST

A pretest to assess the viability of the survey instruments, particularly the questionnaires and the field organization, was carried out in Iringa Rural District, Iringa Region. It covered 16 enumeration areas with a total of 320 households. The pretest, which took a month to complete, was carded out in November/December, 1990, and covered both rural and urban EAs.

The pretest training took two weeks and consisted of classroom training and field practice in neighborhood areas. In all, 14 newly recruited interviewers and the Census staff were involved. The Census staffs who were to be transformed into the TDHS team handled the training for both the fieldwork management and the questionnaire. During the later fieldwork, they supervised the field exercise.

During the fieldwork, the administrative structure of the CCM Party, which involved the Party Branch Offices and the ten-cell leadership, were utilized in an effort to secure the maximum confidence and cooperation of the people in the areas where the team was working. At the end of the fieldwork, the interviewers and the supervisory team returned to the head office in Dares Salaam for debriefing and discussion of their field experiences, particularly those related to the questionnaires and the logistic problems that were encountered. All these experiences were used to improve upon the final version of the questionnaires and the overall logistic arrangements.

Response rate

Out of the 9282 households selected for interview, 8561 households could be located and 8327 were actually interviewed. The shortfall between selected and interviewed households was largely due to the fact that many dwellings were either vacant or destroyed or no competent respondents were present at the time of the interview. A total of 9647 eligible women (i.e., women age 15-49 who spent the night before the interview in a sampled household) were identified for interview, and 9238 women were actually interviewed (96 percent response rate). The main reason for non-interview was absence from the home or incapacitation.

The Tanzania DHS male survey covered men aged between 15 and 60 years who were living in selected households (every fourth household of the female survey). The results of the survey show that 2392 eligible men were identified and 2114 men were interviewed (88 percent response rate). Men were generally not interviewed because they were either incapacitated or not at home during the time of the survey.

Sampling error estimates

The results from sample surveys are affected by two types of errors, non-sampling error and sampling error. Non-sampling error is due to mistakes made in carrying out field activities, such as failure to locate and interview the correct household, errors in the way the questions are asked, misunderstanding on the part of either the interviewer or the respondent, and data entry errors. Although efforts were made to minimize this type of error during the design and implementation of the TDHS, non-sampling errors are impossible to avoid and difficult to evaluate statistically.

Sampling errors, on the other hand, can be measured statistically. The sample of women selected in the TDHS is only one of many samples that could have been selected from the same population, using the same design and expected size. Each one would have yielded results that differed somewhat from the actual sample selected. The sampling error is a measure of the variability between all possible samples; although it is not known exactly, it can be estimated from the survey results.

Sampling error is usually measured in terms of standard error of 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 one can be reasonably assured that, apart from non-sampling errors, the true value of the variable for the whole population falls. For example, for any given statistic calculated from a sample survey, the value of that same statistic as measured in 95 percent of all possible samples with the same design (and expected size) will fall within a range of plus or minus two times the standard error of that statistic.

If the sample of women had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the Tanzania DHS sample designs depended on stratification, stages, and clusters. Consequently, it was necessary to utilize more complex formulas. The computer package CLUSTERS, developed by the International Statistical

Analysis unit

Woman, Child, Birth, and Household Member

Universe

Women age 15-49, Children age 0-4, Births, and All persons in Tanzania 2015

Kind of data

Sample survey data [ssd]

Sampling procedure

MICRODATA SOURCE: Ministry of Health, Community Development, Gender, Elderly and Children [Tanzania], Ministry of Health [Zanzibar], National Bureau of Statistics [Tanzania], Office of the Chief Government Statistician, and ICF

SAMPLE UNIT: Woman SAMPLE SIZE: 13,266

SAMPLE UNIT: Child SAMPLE SIZE: 10,233

SAMPLE UNIT: Birth SAMPLE SIZE: 37,169

SAMPLE UNIT: Household Member SAMPLE SIZE: 64,880

Mode of data collection

Face-to-face [f2f]

Concentration Indices for accessing safe childbirth care with household ranked by socioeconomic in Tanzania DHS, 2004–2016.

Abstract

This 2011-12 Tanzania HIV/AIDS and Malaria Indicator Survey (THMIS) was implemented by the National Bureau of Statistics (NBS) in collaboration with the Office of the Chief Government Statistician (OCGS-Zanzibar) from December 16, 2011, to May 24, 2012.The Tanzania Commission for AIDS (TACAIDS) and the Zanzibar AIDS Commission authorized the National Bureau of Statistics (NBS) to conduct the 2011-12 THMIS. The survey covers both the Tanzania Mainland and Zanzibar.

The objectives of the 2011-12 THMIS were to collect data on knowledge and behaviour regarding HIV/AIDS and malaria, measure HIV prevalence among women and men age 15-49, and measure the presence of malaria parasites and anaemia among children age 6-59 months. The 2011-12 THMIS follows up on the 2007-08 THMIS and the 2003-04 Tanzania HIV/AIDS Indicator Survey (THIS). The 2011-12 THMIS also updates estimates of selected basic demographic and health indicators covered in previous surveys, including the 1991-92 Tanzania Demographic and Health Survey (TDHS), the 1996 TDHS, the 1999 Reproductive and Child Health Survey, the 2004-05 TDHS, and the 2010 TDHS.

Geographic coverage

National coverage

Analysis unit

• Individuals
• Households

Universe

The survey covered all de jure household members (usual residents), all eligible men and women aged between 15-49 years, and all children age 6-59 months in the household.

Kind of data

Sample survey data [ssd]

Sampling procedure

The sampling frame used for the 2011-12 THMIS was developed by the National Bureau of Statistics (NBS) after the 2002 Population and Housing Census (PHC) and is the same as that used for the 2010 and 2004-05 Tanzania Demographic and Health Surveys (TDHS), the 2007-2008 THMIS, and the 2003-04 Tanzania HIV and AIDS Indicator Survey (THIS). The sampling frame excluded nomadic and institutional populations such as persons in hotels, barracks, and prisons.

The 2011-12 THMIS was designed to allow estimates of key indicators for each of Tanzania's 30 regions. The sample was selected in two stages. The first stage involved selecting sample points (clusters) consisting of enumeration areas (EAs) delineated for the 2002 PHC. A total of 583 clusters were selected.On the Mainland, 30 sample points were selected in Dar es Salaam and 20 were selected in each of the other 24 regions.2 In Zanzibar, 15 sample points were selected in each of the five regions.

The second stage of selection involved the systemic sampling of households. A household listing operation was undertaken in all the selected areas prior to the fieldwork. From these lists, households to be included in the survey were selected. Approximately 18 households were selected from each sample point for a total sample size of 10,496 households.

The sampling procedures are more fully described in "Tanzania HIV/AIDS and Malaria Indicator Survey 2011-2012 - Final Report" pp.4-5.

Mode of data collection

Face-to-face [f2f]

Research instrument

Two questionnaires were used for the 2011-12 THMIS: the Household Questionnaire and the Individual Questionnaire. These questionnaires are based on the MEASURE DHS standard AIDS Indicator Survey and Malaria Indicator Survey questionnaires and were adapted to reflect the population and health issues relevant to Tanzania. Input was solicited from various stakeholders representing government ministries and agencies, nongovernmental organizations, development partners, and international donors. After the preparation of the definitive questionnaires in English, the questionnaires were translated into Kiswahili.

The Household Questionnaire was used to list all the usual members and visitors of selected households. Some basic demographic information was collected on the characteristics of each person, including his or her age, sex, education, and relationship to the head of the household. For children under age 18, survival status of the parents was determined. The data on age and sex of household members obtained in the Household Questionnaire was used to identify women and men who were eligible for the individual interview and HIV testing. 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 haemoglobin and malaria testing results for children age 6-59 months.

The Individual Questionnaire was used to collect information from all eligible women and men age 15-49. These respondents were asked questions on the following topics: - Background characteristics (education, media exposure, etc.) - Marriage and sexual activity - Employment - Awareness and behaviour regarding HIV/AIDS and other sexually transmitted infections (STIs) - Knowledge and awareness of malaria - Other health issues

Female respondents were asked to provide their birth history for the six years preceding the interview and information about recent fever and treatment of fever for children born since January 2006.

Response rate

A total of 10,496 households were selected for the sample, from both Mainland Tanzania and Zanzibar. Of these, 10,226 were found to be occupied at the time of the survey. A total of 10,040 households were successfully interviewed, yielding a response rate of 98 percent. In the interviewed households, 11,423 women were identified as eligible for the individual interview. Completed interviews were obtained for 10,967 women, yielding a response rate of 96 percent. Of the 9,388 eligible men identified, 8,352 were successfully interviewed (89 percent response rate).

The principal reason for nonresponse among both eligible women and men was the failure to find them at home despite repeated visits to the households. The lower response rate among men than among women was due to the more frequent and longer absences of men from the households.

Sampling error estimates

The estimates from a sample survey are affected by two types of errors: non-sampling errors and 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 2011-12 Tanzania HIV/AIDS and Malaria Indicator Survey (2011-12 THMIS) to minimize this type of error, non-sampling 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 2011-12 THMIS 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 among all possible samples. Although the degree of variability is not known exactly, it can be estimated from the survey results.

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 2011-12 THMIS sample is the result of a multi-stage stratified design, and, consequently, it was necessary to use more complex formulas. Sampling errors are computed by SAS, using programs developed by ICF International. These programs use the Taylor linearization method of variance estimation for survey estimates that are means, proportions, or ratios. The Jackknife repeated replication method is used for variance estimation of more complex statistics such as fertility and mortality rates.

The estimates of sampling error are more fully described in appendix B in document "Tanzania HIV/AIDS and Malaria Indicator Survey 2011-2012 - Final Report" pp.199-200.

Data appraisal

A series of data quality tables are available to review the quality of the data and include the following:

• Age distribution of the household population
• Age distribution of eligible and interviewed women
• Age distribution of eligible and interviewed men
• Completeness of reporting

The results of each of these data quality tables are shown in appendix C in document "Tanzania HIV/AIDS and Malaria Indicator Survey 2011-2012 - Final Report" pp.227-229.

Contributing factors to the inequalities in accessing skilled birth attendance in Tanzania DHS, 2004–2016.

IntroductionThe prevalence of adverse pregnancy outcomes remains one of the public issues that needs to be addressed in low- and middle-income countries (LMICs), including Tanzania. Despite evidence on the effectiveness of antenatal care (ANC) services in addressing adverse pregnancy outcomes, empirical studies are scarce. Therefore, this study aims to analyze the impact of ANC services on adverse pregnancy outcomes.MethodsThis is a retrospective study that uses secondary data from the Tanzania Demographic and Health Survey for 2022. The impact of ANC services on adverse pregnancy outcomes was estimated using Propensity Score Matching (PSM), and the robustness of results was checked using doubly robust estimatorsResultsAdequate ANC services utilization reduces adverse pregnancy outcomes in Tanzania. Specifically, adequate ANC services utilization reduces adverse pregnancy outcomes: 5.6%–8.2% (depending on the PSM approach used). Similarly, an adequate ANC package reduces adverse pregnancy outcomes: 6.3%–9.3% (depending on the PSM approach used).ConclusionsThe prevalence of adverse pregnancy outcomes needs to be addressed through adherence to ANC services utilization. Despite the utilization of ANC services being influenced by social, economic, and demographic factors, it is important to ensure essential packages of services are delivered to a pregnant woman for better pregnancy outcomes, as our results show that ANC visits alone have no significant impact.