Measuring Living Standards within Cities, Dar es Salaam 2014-2015 - Tanzania

Abstract
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The Measuring Living Standards in Cities (MLSC) survey is a new instrument designed to enhance understanding of cities in Africa and support evidence based policy design. The instrument was developed under the World Bank’s Spatial Development of African Cities Program, and was piloted in Dar es Salaam (Tanzania) and Durban (South Africa) over the course of 2014/15. These geo-referenced surveys provide information on urban living standards at an unprecedented level of granularity: they can be compared across different geographic levels within the cities, and between areas of ‘regular’ and ‘irregular’ settlement patterns. They also respond to the need to increased understanding of specifically ‘urban’ dimensions of quality of living: housing attributes, access to basic services, and commuting patterns, among others.

Geographic coverage
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The survey covered households in Dar es Salaam, Tanzania.

Analysis unit
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- Household

- Individual

Kind of data
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Sample survey data [ssd]

Sampling procedure
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SAMPLE FRAME

16,000 EAs generated by the Tanzania National Bureau of Statistics (NBS) for the 2012 Census.

STAGE ONE

200 EAs sorted into four strata. The central strata was divided into ‘central core, shanty’ and ‘central core, non-shanty’. Two EAs were replaced with reserve EAs as the original EAs were found to be inaccessible.

STAGE TWO

12 households randomly selected by systematic equal-probability from updated listing of each EA.

LISTING METHODOLOGY

The listing exercise took place between the first and the second stage of sampling. The household listing operations were implemented with computer assisted paperless interviewing (CAPI) techniques, which generates electronic files directly. Enumerators collected basic information about household: the name of the household head name, phone number and total number of household members living in the dwelling. Enumerators also recorded the GPS location of all structures,18 defined the type of structure, and aimed to provide measurement of structure size.

Listing was preceded by community sensitisation in both cities. In Dar es Salaam, enumerators visited the local chief (Mjumbe) of their assigned EA two days in advance of listing and on the day of listing.

Enumerators were equipped with maps created on Google My Maps to display shapefiles for the listing exercise. Hardcopies of their respective EA maps were also provided to be use in case of network failure. In Dar es Salaam, enumerators conducted a listing of all households in each of the selected EAs.

The listing exercise was conducted by 30 enumerators, each of which was assigned between 3 and 9 EAs for listing (enumerators were selected on the basis of performance from a group of 35 that were trained for listing). Enumerators were allocated EAs based on: (i) distance from enumerators’ homes in order to minimize transport time and cost; (ii) distance between the EAs; and (iii) safety and response rate considerations.

SURVEY IMPLEMENTATION

The surveys were fielded over the course of several months. The Dar es Salaam survey was implemented between November 2014 and January 2015.

Cases were assigned to interviewers using Survey Solutions. Interviewers were provided with both an electronic and hardcopy map, as well as a printed completion form, and could contact the listing manager through email, WhatsApp, or google hangouts if they were unable to find the assigned house.

Completing the survey often required repeat visits. This is because the survey required input from up to three separate respondents: the main respondent, who could be any present household member, and answered questions on household composition, basic information on members, assets, remittances, grants, housing, properties and consumption; the household head, who answered questions on residential history, satisfaction, employment, time use and commuting; and a random respondent, who was randomly selected from household members over the age of 12 (not including the head), who responded questions on satisfaction, employment, time use and commuting. Enumerators visited each house at least twice before a component could be marked as unavailable - in many cases, however, more than two visits were conducted.

Quality assurance procedures included: (i) In-interview feedback from CAPI, which provided a check that modules or questions were not missing, and alerted interviewers to mistakes and inconsistencies in given answers, so that these could be addressed while the interviewer was still with the respondent; (ii) Aggregate checks conducted using the Survey Solutions Supervisor application, which allows supervisors to identify common mistakes (applied to all initial interviews, and then through spot checks); interviewer performance and completion monitoring conducted by the implementing firm, through interviewer and EA level summaries of response rates, interview completion, and progress; (iii) weekly summaries of key indictors provided by the World Bank team (following each data delivery); (iv) direct observation of fieldwork; and (v) back check interviews. A key lesson learned is that the portion of back check interviews should be agreed in advance with the implementing firm: in Dar es Salaam back checks were conducted on 5% of the sample.

Mode of data collection
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Computer Assisted Personal Interview [capi]

Response rate
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Non-response rate: 13%

摘要
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《城市生活标准测量》（MLSC）调查是一项旨在深化对非洲城市理解并支持基于证据的政策设计的创新工具。该工具在世行非洲城市空间发展计划下开发，并于2014/15年间在坦桑尼亚达累斯萨拉姆和南非德班进行试点。这些具有地理参考的调查研究以史无前例的精细程度提供了关于城市生活标准的信息：它们可以在城市内部不同地理层次之间，以及‘常规’和‘非正规’居住模式地区之间进行比较。它们还满足了加深对生活质量的‘城市’维度，尤其是住房属性、基本服务获取和通勤模式等方面的具体理解的需求。
地理覆盖范围
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调查覆盖了坦桑尼亚达累斯萨拉姆的家庭。
分析单元
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- 家庭
- 个人
数据类型
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样本调查数据 [ssd]
抽样程序
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抽样框架

由坦桑尼亚国家统计局（NBS）为2012年人口普查生成的16,000个住宅区（EAs）。
第一阶段

将200个EAs分为四个层阶。中央层阶被划分为‘核心区域，简陋房屋’和‘核心区域，非简陋房屋’。由于原始EAs被认为难以进入，因此用储备EAs替换了两个EAs。
第二阶段

从每个EAs的最新名单中随机系统地以等概率选择12个家庭。
清单方法

清单作业在抽样第一阶段和第二阶段之间进行。家庭清单操作采用计算机辅助的无纸化访谈（CAPI）技术实施，可直接生成电子文件。调查员收集了关于家庭的基本信息：户主姓名、电话号码以及居住在该住所中的家庭成员总数。调查员还记录了所有建筑物的GPS位置，定义了建筑物的类型，并旨在提供建筑规模的测量。
清单作业在两座城市都进行了社区敏感性提升。在达累斯萨拉姆，调查员在清单作业前两天和当天访问了分配给其EAs的当地首领（Mjumbe）。
调查员配备了在Google My Maps上创建的地图，用于显示清单作业的shapefiles。还提供了各自EAs地图的硬拷贝，以防网络故障。在达累斯萨拉姆，调查员对每个选定EAs中的所有家庭进行了清单作业。
清单作业由30名调查员进行，每人被分配3至9个EAs进行清单作业（调查员是从为清单作业培训的35人小组中根据表现选出的）。EAs的分配基于：（i）调查员家与EAs的距离，以最大限度地减少交通时间和成本；（ii）EAs之间的距离；（iii）安全和响应率考虑。
调查实施

调查在数月内进行。达累斯萨拉姆的调查于2014年11月至2015年1月实施。
使用Survey Solutions将案例分配给访谈者。访谈者得到了电子版和纸质版地图以及填写完成的表格，如果他们找不到分配的房屋，可以通过电子邮件、WhatsApp或Google Hangouts联系清单经理。
完成调查通常需要重复访问。这是因为调查需要从多达三名不同的受访者那里获得输入：主要受访者，可以是任何在场的家庭成员，并回答有关家庭构成、成员的基本信息、资产、汇款、补助、住房和消费等问题；户主，回答有关居住历史、满意度、就业、时间使用和通勤问题；以及随机受访者，从12岁以上的家庭成员中随机选择（不包括户主），回答有关满意度、就业、时间使用和通勤问题。调查员在某个部分被标记为不可用之前至少访问每家两次——然而，在许多情况下，进行了超过两次的访问。
质量保证程序包括：（i）来自CAPI的访谈中反馈，这提供了检查模块或问题是否缺失的依据，并警告访谈员有关答案中的错误和不一致，以便在访谈员仍在受访者身边时解决这些问题；（ii）使用Survey Solutions监督员应用程序进行的汇总检查，该应用程序允许监督员识别常见错误（适用于所有初始访谈，然后通过抽查）；通过访谈员和EAs层面的响应率、访谈完成情况和进度进行的实施公司访谈员表现和完成情况监控；（iii）世界银行团队提供的关键指标每周总结（在每次数据交付后）；（iv）对现场工作的直接观察；（v）复查访谈。一个重要的教训是，应在事先与实施公司达成一致的情况下确定复查访谈的比例：在达累斯萨拉姆，对5%的样本进行了复查。
数据收集方式
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计算机辅助个人访谈 [capi]
响应率
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非响应率：13%