Enterprise Survey 2013 - Yemen, Rep.

Abstract
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This survey was conducted in Yemen between March 2013 and July 2014 as part of the joint World Bank/European Bank for Reconstruction and Development (EBRD)/European Investment Bank (EIB) Enterprise Survey. The objective of the survey is to obtain feedback from enterprises on the state of the private sector as well as to help in building a panel of enterprise data that will make it possible to track changes in the business environment over time, thus allowing, for example, impact assessments of reforms. Through interviews with firms in the manufacturing and services sectors, the survey assesses the constraints to private sector growth and creates statistically significant business environment indicators that are comparable across countries.

The standard Enterprise Survey topics include firm characteristics, gender participation, access to finance, annual sales, costs of inputs/labor, workforce composition, bribery, licensing, infrastructure, trade, crime, competition, capacity utilization, land and permits, taxation, informality, business-government relations, innovation and technology, and performance measures. Over 90% of the questions objectively ascertain characteristics of a country's business environment. The remaining questions assess the survey respondents' opinions on what are the obstacles to firm growth and performance.

Geographic coverage
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National

Analysis unit
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The primary sampling unit of the study is the establishment. An establishment is a physical location where business is carried out and where industrial operations take place or services are provided. A firm may be composed of one or more establishments. For example, a brewery may have several bottling plants and several establishments for distribution. For the purposes of this survey an establishment must make its own financial decisions and have its own financial statements separate from those of the firm. An establishment must also have its own management and control over its payroll.

Universe
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The whole population, or universe of the study, is the non-agricultural economy. It comprises: all manufacturing sectors according to the group classification of ISIC Revision 3.1: (group D), construction sector (group F), services sector (groups G and H), and transport, storage, and communications sector (group I). Note that this definition excludes the following sectors: financial intermediation (group J), real estate and renting activities (group K, except sub-sector 72, IT, which was added to the population under study), and all public or utilities-sectors.

Kind of data
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Sample survey data [ssd]

Sampling procedure
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The sample was selected using stratified random sampling. Three levels of stratification were used in this country: industry, establishment size, and region.

Industry stratification was designed in the way that follows: the universe was stratified into one collective manufacturing industry, and two services industries (retail and other services).

Size stratification was defined following the standardized definition for the rollout: small (5 to 19 employees), medium (20 to 99 employees), and large (more than 99 employees). For stratification purposes, the number of employees was defined on the basis of reported permanent full-time workers. This seems to be an appropriate definition of the labor force since seasonal/casual/part-time employment is not common practice, apart from the construction and agriculture sectors which are not included in the survey.

Regional stratification was defined in 6 regions (due to classifications in the sample frame, regions were defined at the governorate level) throughout Yemen. The six regional strata included were Amanat Al-Asemah (Sana'a), Aden, Hudaydah, Hadramaut, Ibb, and Taizz.

For Yemen, two sample frames were used. The first was supplied by the World Bank and consisted of enterprises interviewed in Yemen in 2010. The World Bank required that attempts should be made to re-interview establishments responding to Yemen, Rep. Enterprise Survey 2010, where they met eligibility criteria. This sample is referred to as the panel. The second sample frame, referred to as the fresh sample, was obtained from the Central Statistics Office 2010 Establishment Census, with updates and validation provided by Yemen Polling Center.

The enumerated establishments were then used as the frame for the selection of a sample with the aim of obtaining interviews at 360 establishments with five or more employees. Given the impact that non-eligible units included in the sample universe may have on the results, adjustments may be needed when computing the appropriate weights for individual observations. The percentage of confirmed non-eligible units as a proportion of the total number of sampled establishments contacted for the survey was 14.5% (165 out of 1,141 establishments).

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

Research instrument
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The following survey instruments are available:
- Manufacturing Questionnaire;
- Services Questionnaire.

All variables are named using, first, the letter of each section and, second, the number of the variable within the section, i.e. a1 denotes section A, question 1. Variable names proceeded by a prefix "MNA" indicate questions specific to the Middle East and North Africa region, therefore, they may not be found in the implementation of the rollout in other countries. All other suffixed variables are global and are present in all economy surveys over the world. All variables are numeric with the exception of those variables with an "x" at the end of their names. The suffix "x" denotes that the variable is alpha-numeric.

There are two establishment identifiers, idstd and id. The first is a global unique identifier. The second is a country unique identifier. The variables a2 (sampling region), a6a (sampling establishment's size), and a4a (sampling sector) contain the establishment's classification into the strata chosen for each country using information from the sample frame. The strata were defined according to the guidelines described above. Variable a4a is coded using ISIC Rev 3.1 codes for the chosen industries for stratification. These codes include most manufacturing industries (15 to 37), retail (52), and (45, 50, 51, 55, 60-64, 72) for other services.

Cleaning operations
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Data entry and quality controls are implemented by the contractor and data is delivered to the World Bank in batches (typically 10%, 50% and 100%). These data deliveries are checked for logical consistency, out of range values, skip patterns, and duplicate entries. Problems are flagged by the World Bank and corrected by the implementing contractor through data checks, callbacks, and revisiting establishments.

Response rate
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The number of contacted establishments per realized interview was 0.31. This number is the result of two factors: explicit refusals to participate in the survey, as reflected by the rate of rejection (which includes rejections of the screener and the main survey) and the quality of the sample frame, as represented by the presence of ineligible units. The number of rejections per contact was 0.15.

Item non-response was addressed by two strategies:
a- For sensitive questions that may generate negative reactions from the respondent, such as corruption or tax evasion, enumerators were instructed to collect the refusal to respond as a different option from don’t know.
b- Establishments with incomplete information were re-contacted in order to complete this information, whenever necessary.

Survey non-response was addressed by maximizing efforts to contact establishments that were initially selected for interview. Attempts were made to contact the establishment for interview at different times/days of the week before a replacement establishment (with similar strata characteristics) was suggested for interview. Survey non-response did occur but substitutions were made in order to potentially achieve strata-specific goals.

摘要
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本调查于2013年3月至2014年7月在也门进行，作为世界银行、欧洲复兴开发银行（EBRD）和欧洲投资银行（EIB）联合企业调查的一部分。调查的目的是收集企业对私营部门状况的反馈，并有助于构建企业数据面板，从而能够追踪商业环境随时间的变化，从而允许进行例如改革影响的评估。通过访谈制造业和服务业的企业，本调查评估了私营部门增长的制约因素，并创建了具有统计学意义的、可跨国家比较的商业环境指标。

标准企业调查主题包括企业特征、性别参与、融资渠道、年销售额、投入/劳动力成本、劳动力构成、贿赂、许可、基础设施、贸易、犯罪、竞争、产能利用率、土地和许可、税收、非正式性、商业与政府关系、创新与技术，以及绩效指标。超过90%的问题客观地确定了国家商业环境的特征。其余问题评估了调查受访者对企业增长和绩效的障碍的看法。

地理覆盖范围
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全国

分析单元
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研究的主要抽样单元是单位。单位是指进行商业活动并进行工业操作或提供服务的地方。一个企业可能由一个或多个单位组成。例如，一个啤酒厂可能有几个灌装厂和几个分销单位。在本调查中，单位必须能够独立做出财务决策，并拥有与企业的财务报表分开的财务报表。单位还必须拥有自己的管理和对其工资单的控制。

总体
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研究的总体，即研究范围，是非农业经济。它包括：根据ISIC修订版3.1的分组分类的所有制造业部门（分组D）、建筑部门（分组F）、服务业部门（分组G和H），以及运输、仓储和通信部门（分组I）。请注意，此定义排除了以下部门：金融中介（分组J）、房地产和租赁活动（分组K，除子部门72，IT外，该子部门已纳入研究范围），以及所有公共或公用事业部门。

数据类型
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样本调查数据 [ssd]

抽样程序
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样本是通过分层随机抽样选取的。在本国使用了三个分层级别：行业、单位规模和地区。

行业分层的设计如下：总体被分为一个集体制造业行业和两个服务业行业（零售和其他服务）。

规模分层是根据标准化的推广定义定义的：小型（5至19名员工）、中型（20至99名员工）和大型（超过99名员工）。为了分层的目的，员工人数是基于报告的永久全职工人数量定义的。这似乎是对劳动力的一种适当定义，因为季节性/临时/兼职就业并不是常见做法，除了不包括在调查中的建筑和农业部门。

地区分层是在也门6个地区（由于样本框架中的分类，地区在省级行政级别上定义）中定义的。六个地区层包括阿曼特·阿尔·阿塞马（萨那）、亚丁、荷台达、哈达拉毛、伊卜和塔伊兹。

对于也门，使用了两个样本框架。第一个是由世界银行提供的，包括在2010年在也门接受访谈的企业。世界银行要求，应尽力重新访谈符合也门、共和国企业调查2010年资格标准的单位。这个样本被称为面板。第二个样本框架，被称为新鲜样本，是从中央统计局2010年单位普查中获得，并由也门民意调查中心提供更新和验证。

然后，列举的单位被用作选择样本的框架，目的是在360个拥有五个或更多员工的单位中进行访谈。鉴于样本总体中包含的非合格单位可能对结果产生的影响，在计算单个观察值的适当权重时可能需要进行调整。确认的非合格单位占调查中联系到的样本单位总数的14.5%（165个单位中的1,141个）。

数据收集方式
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面对面 [f2f]

研究工具
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以下调查工具可供使用：
- 制造业问卷；
- 服务业问卷。

所有变量均使用每个部分的字母和该部分内变量的编号命名，即a1表示部分A，问题1。以“MNA”为前缀的变量表示针对中东和北非地区特定的问题，因此它们可能不在其他国家推广的实施中找到。所有其他后缀变量都是全球性的，在世界各地的经济调查中均存在。所有变量都是数值型的，除非变量名称以“x”结尾。后缀“x”表示该变量是字母数字型的。

有两个单位标识符，idstd和id。第一个是全球唯一标识符。第二个是国家唯一标识符。变量a2（抽样区域）、a6a（抽样单位的规模）和a4a（抽样行业）包含单位分类到每个国家选择的层，使用样本框架中的信息。层是根据上述指南定义的。变量a4a使用ISIC Rev 3.1代码对选择的行业进行编码。这些代码包括大多数制造业行业（15至37）、零售（52）以及（45、50、51、55、60-64、72）的其他服务。

数据清洗操作
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数据输入和质量控制由承包商实施，数据以批量形式（通常是10%、50%和100%）交付给世界银行。这些数据交付将检查逻辑一致性、超出范围的值、跳过模式以及重复条目。问题由世界银行标记并由实施承包商通过数据检查、回调和重访单位进行纠正。

响应率
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每实现一次访谈的接触单位数量为0.31。这个数字是两个因素的结果：明确拒绝参与调查，如反映在拒绝率（包括筛选器和主要调查的拒绝）中，以及样本框架的质量，如通过不合格单位的出现表示。每个联系点的拒绝数量为0.15。

针对项目非响应采取了两种策略：
a- 对于可能引起受访者负面反应的敏感问题，例如腐败或逃税，调查员被指示将拒绝回答作为一个不同于不知道的选项收集。
b- 对于信息不完整的单位，在必要时重新联系以完成这些信息。

针对调查非响应采取的策略是，通过最大化努力联系最初选定的访谈单位。在建议用具有相似层特征的单位替换之前，尝试在周的不同时间/日子联系单位进行访谈。虽然发生了调查非响应，但进行了替换，以有可能实现层特定目标。