National Panel Survey 2012-2013 - Tanzania

Abstract
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The main objective of the NPS is to provide high-quality household-level data to the Tanzanian government and other stakeholders for monitoring poverty dynamics, tracking the progress of the MKUKUTA II poverty reduction strategy1, and to evaluate the impact of other major, national level government policy initiatives. As an integrated survey covering a number of different socioeconomic factors, it compliments other more narrowly focused survey efforts, such as the Demographic and Health Survey on health, the Integrated Labour Force Survey on labour markets, the Household Budget Survey on expenditure, and the National Sample Census of Agriculture. Secondly, as a panel household survey in which the same households are revisited over time, the NPS allows for the study of poverty and welfare transitions and the determinants of living standard changes.

Geographic coverage
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Representative at the national, urban/rural and major ago-ecological zones levels.

Analysis unit
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Households and individuals.

Universe
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The survey covers all individuals included in the households in the sample.

The eligibility requirement for the NPS is defined as any household member aged 15 years and above, excluding live-in servants. Households with at least one eligible member where completely interviewed, including any subsequent non-eligible members present in the household. Any household or eligible members that had either moved or split away from a primary household were tracked and interviewed in their new location.

Kind of data
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Sample survey data [ssd]

Sampling procedure
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The original sample size of 3,265 households for the 2008/2009 survey was designed to be representative at the national, urban/rural, and major agro-ecological zones. The total sample size of 3,265 households is clustered in 409 Enumeration Areas (2,063 households in rural areas and 1,202 urban areas) across Tanzania and Zanzibar. The NPS sample allows analysis at 4 primary domains of inference, namely: Dar es Salaam, other urban areas on mainland Tanzania,rural mainland Tanzania, and Zanzibar.

The NPS 2012/2013 revisits all households interviewed during the first two waves; NPS 2008/2009 and NPS 2010/2011. This includes the originally sampled 3,265 households plus split-off households added into the sample in the second round of the NPS.5 Thus the total sample at the onset of the NPS 2012/2013 consisted of 3,924 target households.

The eligibility requirement for the NPS is defined as any household member aged 15 years and above, excluding live-in servants. Households with at least one eligible member where completely interviewed, including any subsequent non-eligible members present in the household. Any household or eligible members that had either moved or split away from a primary household were tracked and interviewed in their new location.

It is important to note that the NPS 2012/2013 sample includes individuals meeting the eligibility requirement that were interviewed as part of the NPS 2008/2009 wave but were not located and interviewed during the NPS 2010/2011. This constituted an additional 703 individuals assigned to their last know associated household. To identify these individuals in the NPS 2012/2013 sample household rosters they received an ID code in the range of 101-130; the ID code was formed by the addition of 100 to their NPS 2008/2009 roster ID.

The resulting sample size for the third round of NPS, including NPS 2008/2009 and NPS 2010/2011 households plus new, or split-off, households in NPS 2012/2013, is 5,015 households. For a more detailed description of the original sample design, please reference the NPS 2008/2009 Basic Information Document.

Sampling deviation
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Panel Attrition

As with most panel surveys a certain portion of panel respondents are not able to be reinterviewed over time. This attrition of panel respondents can lead to attrition bias where respondents drop out of the survey non-randomly and where the attrition is correlated with variables of interest. The TZNPS has fortunately maintained low attrition over the waves, thus minimizing the potential for attrition bias within the datasets.

The target sample of eligible households for the NPS 2012/2013 was 3,924, representing original NPS 2008/2009 households plus new or split-off households added to the NPS in the second round. Of these households 3,786 households were re-located and re-interviewed. This translates to a household attrition rate of roughly 3.50 percent between the NPS 2010/2011 and NPS 2012/2013. At the individual level, 12,280 of the 13,278 eligible household members where reinterviewed during the NPS 2012/2013, equating to an individual attrition rate of roughly 7.52 percent between the NPS 2010/2011 and the NPS 2012/2013.

Total household attrition for the NPS, up to round three, is 4.84 percent.

Mode of data collection
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Face-to-face [f2f]

Research instrument
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The third round of the NPS consists of four survey instruments: a Household Questionnaire, Agriculture Questionnaire, Livestock/Fishery Questionnaire, and a Community Questionnaire. Each of the NPS questionnaires were developed in collaboration with line ministries and donor partners, including the Technical Committee, over a period of several months. The NBS solicited feedback from various stakeholders in regards to survey content and design paying due consideration to comparability with previous panel rounds.

Piloting of the NPS 2012/2013 instruments took place in the Tanga region in July 2012 in conjunction with supervisor training. After piloting, the questionnaires were further revised and finalized in September 2012. Interviewer manuals were developed with detailed instructions for field staff during training and as the main reference guide for the survey over the course of the fieldwork.

The questionnaires for NPS 2012-13 are available in English and Swahili.

Cleaning operations
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Data Processing & Management:

The NPS 2012/2013 contains a robust multi-level quality assurance and data management system. Great effort was placed on the development and utilization of this system by the NBS with technical assistance form the World Bank prior to the implementation of the NPS 2012/2013 to assist in the management of the complex household panel survey and address the growing need for high quality timely data.

The NPS utilizes a concurrent field entry system known a CAFE; Computer Assisted Field Entry. This system was selected to increase the availability of data for review by managing staff as well as to provide regular and consistent quality assessment of data directly to the field staff. As with the earlier rounds, CSPro was used for data entry and initial quality reporting while STATA was utilized to perform complex aggregated checks. Building off the work conducted for the NPS 2010/2011, the NPS 2012/2013 data entry application further develops the quantity and complexity of data quality checking routines while simplifying reporting. Furthermore, due to the panel nature of the survey, where applicable and appropriate, data was checked against previous round data.

As data entry took place while in the interview area, when data issues were identified and reported, field teams would return to households and clarify and correct inconsistent information prior to the transmission of the data to headquarters. Data files from completed clusters were transmitted to NBS headquarters using 3G USB modems. Received data files were concatenated at the headquarters, and regular checks were performed to ensure the fieldwork was proceeding according to the schedule and that quality standards were met. During the course of field work data was routinely checked at the aggregate level to identify any potential issues and where identified additional checks where integrated into the CAFE system.

Throughout the course of field work, the field teams regularly sent the paper questionnaires back to the NBS headquarters for further processing. Once the paper questionnaires and data files for completed EAs were received at NBS headquarters, a double entry procedure was implemented. Six data entry operators were hired by NBS to perform the second data entry for the paper questionnaires into the CSPro-based data entry system for all questionnaires administered. A comparison between the entered values in the field based data entry and headquarters based data entry was conducted and any discrepancies in values between the two were flagged for manual inspection of the physical questionnaire and corrected. The application of the third level of data consistency validation further allowed for the assessment of the quality of the entry work performed by both the field entry staff and the headquarters based entry staff. Regular feedback was supplied to data entry staff resulting in improved quality where needed and overall efficiency.

Additional data cleaning was conducted as the final stage of the data processing. Further adjustment of the data post-entry was conducted under the principle of absolute certainty where adjustments must be evidence based and correction values true beyond a reasonable doubt. As such, the resulting final datasets may still contain some inconsistencies and outliers. Handling of these values is thus left entirely to the data user.

Throughout the data processing system versions of the data are archived at all key steps and all checking and cleaning syntax documented and archived.

摘要
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国家贫困监测调查（NPS）的主要目标是为坦桑尼亚政府和其它利益相关者提供高质量的户级数据，以便监测贫困动态、追踪MKUKUTA II减贫战略的进展，以及评估其他重大国家级政府政策倡议的影响。作为一个涵盖多个不同社会经济因素的综合性调查，NPS补充了其他更专注于特定领域的调查努力，例如健康调查、劳动市场调查、家庭预算调查以及农业人口抽样调查。其次，作为一个时间序列家庭调查，NPS使得研究贫困和福利的转型以及生活水平变化的决定因素成为可能。
地理覆盖范围
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在全国、城市/农村以及主要农业生态区层面上具有代表性。
分析单元
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家庭和个人。
调查范围
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调查涵盖样本家庭中的所有个人。
NPS的资格要求定义为任何15岁及以上的家庭成员，不包括居住家庭的服务人员。具备至少一名合格成员的家庭将进行全面访谈，包括家庭中任何后续的非合格成员。任何已搬家或从主要家庭中分出的家庭或合格成员都将跟踪并在新地点进行访谈。
数据类型
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样本调查数据 [ssd]
抽样程序
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2008/2009年度调查的原始样本量是3,265户，旨在在全国、城市/农村和主要农业生态区具有代表性。3,265户的总样本量被分为409个调查区域（农村地区2,063户，城市地区1,202户），遍布坦桑尼亚和桑给巴尔。NPS样本允许在4个主要推断领域进行分析，即：达累斯萨拉姆、坦桑尼亚大陆的其他城市地区、农村大陆坦桑尼亚和桑给巴尔。
NPS 2012/2013年回访了在第一波访谈的所有家庭；NPS 2008/2009年和NPS 2010/2011年。这包括最初样本中的3,265户以及NPS第二阶段添加到样本中的分家户。因此，NPS 2012/2013年开始时的总样本量为3,924户。
NPS的资格要求定义为任何15岁及以上的家庭成员，不包括居住家庭的服务人员。具备至少一名合格成员的家庭将进行全面访谈，包括家庭中任何后续的非合格成员。任何已搬家或从主要家庭中分出的家庭或合格成员都将跟踪并在新地点进行访谈。
需要注意的是，NPS 2012/2013年的样本包括在NPS 2008/2009波次中访谈且在NPS 2010/2011波次中未找到和访谈的符合资格要求的个人。这构成了额外的703人，他们被分配到其最后已知的关联家庭。在NPS 2012/2013年的样本家庭名单中，这些个人收到了101-130范围内的ID代码；ID代码是通过在NPS 2008/2009名单ID的基础上添加100形成的。
NPS第三轮的最终样本量，包括NPS 2008/2009年和NPS 2010/2011年的家庭以及NPS 2012/2013年的新家庭或分家户，为5,015户。有关原始样本设计的更详细描述，请参阅NPS 2008/2009基本信息文件。
抽样偏差
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面板受访者流失

与大多数面板调查一样，一部分面板受访者随着时间的推移无法重新进行访谈。面板受访者的这种流失可能导致流失偏差，即受访者非随机地退出调查，并且流失与感兴趣的变量相关。幸运的是，TZNPS在各个波次中保持了低流失率，从而最大限度地减少了数据集中的流失偏差。
NPS 2012/2013年的目标合格家庭样本量为3,924户，代表原始NPS 2008/2009家庭以及第二阶段添加到NPS中的新或分家户。在这些家庭中，有3,786户被重新安置并重新访谈。这相当于NPS 2010/2011年和NPS 2012/2013年之间的大约3.50%的家庭流失率。在个人层面，13,278名合格的家庭成员中有12,280人在NPS 2012/2013年进行了重新访谈，相当于NPS 2010/2011年和NPS 2012/2013年之间的大约7.52%的个人流失率。
NPS至今第三轮的总家庭流失率为4.84%。
数据收集方式
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面对面 [f2f]
研究工具
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NPS的第三轮包括四种调查工具：家庭问卷、农业问卷、畜牧/渔业问卷和社区问卷。NPS问卷是在与相关部门和捐助伙伴合作下开发的，包括技术委员会，历时数月。国家统计局征求了各利益相关者对调查内容和设计的反馈，并充分考虑了与先前面板轮次的可比性。
NPS 2012/2013年的工具在2012年7月与监督员培训一起在塔纳地区进行了试点。试点后，问卷在2012年9月进行了进一步的修订和最终确定。在培训期间为现场工作人员开发了访谈手册，作为现场工作期间的主要参考指南。
NPS 2012-13年的问卷可用英语和斯瓦希里语。
数据清洗操作
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数据处理与管理：
NPS 2012/2013年包含一个强大的多层次质量保证和数据管理系统。国家统计局在NPS 2012/2013年的实施前，在世行技术援助下投入了大量努力来开发和利用这个系统，以帮助管理复杂的家庭面板调查，并满足对高质量及时数据的日益增长的需求。
NPS采用了一种称为CAFE的并发现场输入系统；计算机辅助现场输入。该系统被选中是为了增加数据供管理人员审查的可用性，以及为了向现场工作人员提供定期和一致的数据质量评估。与早期各轮次一样，CSPro用于数据输入和初始质量报告，而STATA用于执行复杂的聚合检查。在NPS 2010/2011年的工作中，NPS 2012/2013年的数据输入应用程序进一步开发了数据质量检查例程的数量和复杂性，同时简化了报告。此外，由于调查的面板性质，在适用和适当的情况下，数据与先前轮次的数据进行了核对。
在访谈区域进行数据输入的同时，当识别到数据问题时，现场团队会返回家庭，澄清并纠正不一致的信息，然后再将数据传输到总部。使用3G USB调制解调器将完成簇的数据文件传输到国家统计局总部。接收到的数据文件在总部进行连接，并定期进行检查，以确保现场工作按计划进行并达到质量标准。在实地工作中，数据通常在汇总级别进行检查，以识别任何潜在问题，并在识别到问题后，将额外的检查整合到CAFE系统中。
在整个实地工作过程中，现场团队定期将纸质问卷发送回国家统计局总部进行进一步处理。一旦收到纸质问卷和完成调查区域的EA数据文件，就实施了双重输入程序。国家统计局聘请了6名数据输入操作员进行所有问卷的第二次数据输入，这些问卷基于CSPro的数据输入系统。在基于现场的数据输入和总部基于的数据输入之间进行了值比较，任何两个输入之间值的不一致都会被标记出来，以便进行手动检查物理问卷并进行纠正。应用第三级数据一致性验证进一步允许评估现场输入人员和总部输入人员的数据输入工作质量。对数据输入人员提供了定期反馈，在需要时提高了质量，并总体上提高了效率。
在数据处理的最后阶段进行了额外的数据清洗。在输入后对数据进行进一步的调整，根据绝对确定性原则进行，调整必须基于证据，且纠正值在合理怀疑之外确凿。因此，最终生成的数据集可能仍包含一些不一致和异常值。这些值的处理完全留给数据使用者。
在整个数据处理过程中，所有关键步骤都会存档数据版本，所有检查和清洗语法都会进行记录和存档。