Demographic and Health Survey 2010 - Tanzania

Abstract
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The principal objective of the 2010 Tanzania DHS 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
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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.

Analysis unit
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- Households
- Children under five years
- Women age 15-49
- Men age 15-49

Kind of data
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Sample survey data

Sampling procedure
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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.

Note: See detailed sample implementation in the APPENDIX A of the final 2010 Tanzania Demographic and Health Survey report.

Mode of data collection
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Face-to-face

Research instrument
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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 Engli sh 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.

Response rate
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Response rates are important because a high rate of nonresponse may affect the results. 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
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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 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 2010 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 2010 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 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 mortality rates.

Note: See detailed sampling error calculation in the APPENDIX B of the final report.

Data appraisal
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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
- Nutritional status of children

Note: See these data quality tables in APPENDIX C of the final report.

摘要
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2010年坦桑尼亚DHS（人口与家庭健康调查）的主要目标为收集关于家庭特征、生育水平与偏好、计划生育方法的认识与使用、儿童与成人死亡率、孕产妇健康、母乳喂养实践、孕前保健、儿童免疫与疾病、幼儿及妇女的营养状况、疟疾的预防与治疗、妇女地位、女性割礼、性行为、关于HIV/AIDS的知识与行为，以及家庭暴力发生率的各类数据。
地理覆盖范围
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2010年TDHS样本设计旨在为整个国家、大陆的城乡地区以及桑给巴尔提供估计值。对于特定指标，如避孕药具的使用，样本设计允许对当时26个地区的每个地区进行指标估计。
分析单位
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- 家庭
- 5岁以下儿童
- 15-49岁女性
- 15-49岁男性
数据类型
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样本调查数据
抽样程序
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2010年TDHS样本设计旨在为整个国家、大陆的城乡地区以及桑给巴尔提供估计值。对于特定指标，如避孕药具的使用，样本设计允许对当时26个地区的每个地区进行指标估计。
为了估计某些人口指标的地理差异，大陆坦桑尼亚的地区被合并为七个地理区域。尽管这些并非官方的行政区域，但该分类被MoHSW（卫生与人口部）的生殖与儿童健康部门采用。在每个地理区域中使用了区域分类，以便拥有相对较大的病例数并减少抽样误差。需要注意的是，以下定义的区域与1991-92年和1996年TDHS报告中的区域略有不同，但与2004-05年TDHS和2007-08年THMIS中的区域相同。
- 西部：塔波拉、希尼安加、基戈马
- 北部：基里曼贾罗、塔安加、阿鲁沙、 Manyara
- 中央：多多马、辛迪达
- 南部高地：姆贝亚、伊林加、鲁库瓦
- 湖区：卡盖拉、姆万扎、马拉
- 东方：达累斯萨拉姆、帕尼、莫罗戈罗
- 南部：林迪、姆特瓦拉、鲁武马
- 桑给巴尔：乌琼加北部、乌琼加南部、城镇西部、佩MBA北部、佩MBA南部
从2010年TDHS中选取了10,300个家庭的代表性概率样本。样本在两个阶段进行选择。在第一阶段，从2002年人口和住房普查的普查区域名单中选取了475个簇。在达累斯萨拉姆，选取了25个样本点，在其他20个大陆坦桑尼亚地区各选取了18个。在桑给巴尔，每个地区选取了18个簇，共计90个样本点。
在第二阶段，在所有选定的簇中进行了完整的家庭清单编制，时间为2009年7月至8月。然后，系统性地选择家庭参与调查。在所有地区，每个簇中选取了22个家庭，在达累斯萨拉姆则选取了16个。
所有15-49岁的女性，无论是2010年TDHS样本中家庭内的永久居民还是调查前夜在家庭中的访客，都有资格接受访谈。在所有选定的家庭样本的1/3中，如果男性是家庭内的永久居民或调查前夜在家庭中的访客，则他们有资格接受访谈。
注意：有关详细样本实施情况，请参阅最终2010年坦桑尼亚人口与家庭健康调查报告的附录A。
数据收集方式
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面对面
研究工具
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2010年TDHS使用了三个问卷：家庭问卷、女性问卷和男性问卷。这些问卷的内容基于MEASURE DHS项目开发的模型问卷。为了反映坦桑尼亚人口与健康的相关问题，问卷进行了改编。征求了代表政府各部和机构、非政府组织和国际捐助者的利益相关者的意见。在NBS组织的一个利益相关者会议上讨论了问卷的最终草案。改编后的问卷从2009年7月23日至8月5日进行了预测试。
家庭问卷用于列出所选家庭中的所有常住和访客成员。收集了有关所列每个人的基本特征信息，包括年龄、性别、教育程度和家庭户主的关系。对于18岁以下的儿童，确定了父母的存活状态。家庭问卷的主要目的是确定有资格接受个人访谈的女性和男性。家庭问卷还收集了有关家庭住宅单位特征的信息，例如水源、厕所设施类型、房屋地板使用的材料、耐用消费品的拥有权以及蚊帐的拥有和使用情况。家庭问卷的另一个用途是确定有资格接受家庭暴力模块访谈的女性。
家庭问卷还用于记录15-49岁女性和5岁以下儿童的身高、体重和血红蛋白测量值、家庭使用加碘食盐的情况、是否同意采集血样以测量女性和儿童体内的维生素A和铁，以及是否提供了盐和尿液样本。
女性问卷用于收集所有15-49岁女性的信息。这些女性被问及以下主题的问题：
- 背景（例如，教育程度、居住史、媒体接触）
- 出生史和儿童死亡率
- 怀孕、分娩和产后护理
- 计划生育方法的知识和使用
- 婴儿喂养实践，包括母乳喂养模式
- 生育偏好
- 儿童疾病发作及其对疾病反应，重点是调查前两周内对发热的治疗
- 疫苗接种和儿童疾病
- 婚姻和性行为
- 丈夫的背景和妇女的工作状况
- 与HIV/AIDS和其他性传播感染（STIs）相关的知识、态度和行为
- 家庭暴力
- 女性生殖器切割
- 成人死亡率，包括孕产妇死亡率
- 生殖和泌尿生殖道的瘘管
- 其他健康问题，包括对肺结核和医疗注射的知识
男性问卷用于2010年TDHS样本中每第三个家庭中的所有15-49岁男性。男性问卷收集了与女性问卷类似的大量信息，但由于它不包含详细的生殖史、孕产妇健康或营养问题、瘘管问题或为计算孕产妇死亡率而询问兄弟姐妹的问题，因此它更短。
应答率
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应答率非常重要，因为高比例的非应答可能会影响结果。共选取了10,300个家庭作为样本，其中在数据收集期间发现有9,741个家庭居住。短缺主要发生在建筑物空置或被毁坏的情况下。在9,741个现有家庭中，9,623个家庭成功接受了访谈，家庭应答率为99%。
在受访的家庭中，确定了10,522名有资格接受个人访谈的女性；对10,139名女性进行了完整的访谈，应答率为96%。在选定的家庭样本的子样本中，确定了2,770名有资格的男性，其中91%的人成功接受了访谈。
有资格的女性和男性非应答的主要原因是在反复访问家庭后未能找到他们。男性较低的应答率反映了男性更频繁且更长时间的离家。
抽样误差估计
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样本调查的估计结果受两种类型的误差影响：（1）非抽样误差，和（2）抽样误差。非抽样误差是实施数据收集和数据处理过程中所犯错误的结果，例如未能找到并访谈正确的家庭、访谈员或受访者对问题的误解，以及数据录入错误。尽管在实施2010年坦桑尼亚人口与家庭健康调查（TDHS）期间做出了众多努力以最大限度地减少此类误差，但非抽样误差是不可避免的，且难以从统计上进行评估。
另一方面，抽样误差可以统计评估。2010年TDHS中选定的受访者样本只是从同一人口中可能选择的许多样本之一，使用相同的设计和预期规模。这些样本中的每一个都会产生与实际选定样本结果略有不同的结果。抽样误差是衡量所有可能样本之间差异的一种度量。虽然变异程度并不完全清楚，但它可以从调查结果中估计出来。
抽样误差通常以特定统计量（平均值、百分比等）的标准误差来衡量，这是方差的平方根。标准误差可用于计算置信区间，在这个区间内可以合理地假设人口的真实值。例如，对于从样本调查中计算出的任何给定统计量，该统计量的值将在95%的所有可能样本的相同大小和设计中落在该统计量的标准误差的两倍范围内。
如果受访者样本被选为简单随机样本，则可以使用简单的公式来计算抽样误差。然而，2010年TDHS样本是多层次分层设计的产物，因此有必要使用更复杂的公式。用于计算2010年TDHS抽样误差的计算机软件是ISSA抽样误差模块。该模块使用Taylor线性化方法对调查估计值进行方差估计，这些估计值是平均值或比例。对于更复杂的统计量，如生育率和死亡率，使用Jackknife重复复制方法进行方差估计。
注意：有关详细的抽样误差计算，请参阅最终报告的附录B。
数据评估
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数据质量表
- 家庭年龄分布
- 有资格和接受访谈的妇女年龄分布
- 报告的完整性
- 按日历年份出生
- 死亡时年龄按天数报告
- 死亡时年龄按月份报告
- 儿童的营养状况
注意：有关这些数据质量表，请参阅最终报告的附录C。