Enterprise Survey 2010-2013, Panel Data - Yemen, Rep.

Abstract
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The documented dataset covers Enterprise Survey (ES) panel data collected in Yemen in 2010 and 2013, as part of the Middle East and North Africa Enterprise Surveys rollout, an initiative of the World Bank.

New Enterprise Surveys target a sample consisting of longitudinal (panel) observations and new cross-sectional data. Panel firms are prioritized in the sample selection, comprising up to 50% of the sample in the current wave. For all panel firms, regardless of the sample, current eligibility or operating status is determined and included in panel datasets.

Yemen ES 2013 was conducted between March 2013 and July 2014 as part of the joint World Bank, European Bank for Reconstruction and Development (EBRD) and European Investment Bank (EIB) Enterprise Survey. Yemen ES 2010 was carried out between March and June 2010.

The objective of the Enterprise 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.

Stratified random sampling was used to select the surveyed businesses. The data was collected using face-to-face interviews.

Data from 830 establishments was analyzed: 214 businesses were from 2013 ES only, 338 - from 2010 ES only, and 278 firms were from both 2010 and 2013 panels.

Geographic coverage
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National

Analysis unit
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The primary sampling unit of the study is an 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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For Yemen ES 2013, 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 were made to re-interview establishments responding to the Yemen 2010 Enterprise Survey where they met eligibility criteria. This sample is referred to as the panel. The second sample frame, referred to as a fresh sample, was obtained from the Central Statistics Office, 2010 Establishment Census, with updates and validation provided by the Yemen Polling Center (YPC).

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

Research instrument
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The following survey instruments were used for Yemen 2013 ES:
- Manufacturing Questionnaire;
- Services Questionnaire.

The survey is fielded via manufacturing or services questionnaires in order not to ask questions that are irrelevant to specific types of firms, e.g. a question that relates to production and nonproduction workers should not be asked of a retail firm. In addition to questions that are asked across countries, all surveys are customized and contain country-specific questions. An example of customization would be including tourism-related questions that are asked in certain countries when tourism is an existing or potential sector of economic growth.

The eligible manufacturing industries have been surveyed using the Manufacturing Module Questionnaire (includes a common set of core variables, plus manufacturing specific questions). Eligible service establishments have been covered using the Services Module Questionnaire. Each variation of the questionnaire is identified by the index variable, a0.

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.

The following survey instruments were used for Yemen 2010 ES:
- Core Questionnaire + Manufacturing Module [ISIC Rev.3.1: 15-37]
- Core Questionnaire + Retail Module [ISIC Rev.3.1: 52]
- Core Questionnaire [ISIC Rev.3.1: 45, 50, 51, 55, 60-64, 72]

The "Core Questionnaire" is the heart of the Enterprise Survey and contains the survey questions asked of all firms across the world. There are also two other survey instruments- the "Core Questionnaire + Manufacturing Module" and the "Core Questionnaire + Retail Module."

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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Survey non-response must be differentiated from item non-response. The former refers to refusals to participate in the survey altogether whereas the latter refers to the refusals to answer some specific questions. Enterprise Surveys suffer from both problems and different strategies were used to address these issues.

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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本记录的数据集涵盖了2010年和2013年在也门收集的企业调查（ES）面板数据，作为中东和北非企业调查推广活动的一部分，该活动由世界银行发起。

新的企业调查旨在针对包含纵向（面板）观测值和新横截面数据的样本。在样本选择中，优先考虑面板企业，占当前波次样本的50%以上。对于所有面板企业，无论样本如何，都会确定并包括其当前的资格或运营状态。

2013年也门ES调查于2013年3月至2014年7月进行，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。2010年也门ES于2010年3月至6月进行。

企业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，调查评估了私营部门增长的制约因素，并创建了具有统计显著性的、可跨国家比较的商业环境指标。

地理覆盖范围
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全国

分析单元
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本研究的主要抽样单元为一个企业。企业是指进行商业活动、工业运营或提供服务的地方。一个公司可能由一个或多个企业组成。例如，一个啤酒厂可能有几个灌装厂和几个分销企业。在本调查中，企业必须能够做出自己的财务决策，并拥有与公司分开的财务报表。企业还必须拥有自己的管理和对其工资单的控制权。

总体
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研究的总体，即研究的全体，是非农业经济。它包括：根据ISIC修订版3.1的行业分组分类的所有制造业部门（组D）、建筑业部门（组F）、服务业部门（组G和H），以及运输、仓储和通信部门（组I）。请注意，此定义不包括以下部门：金融中介（组J）、房地产和租赁活动（组K，除子部门72，IT，该子部门已被纳入研究总体），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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2013年也门ES使用了两个样本框架。第一个由世界银行提供，包括在也门接受2010年调查的企业。世界银行要求尝试重新访谈在2010年也门企业调查中符合资格的企业。此样本被称为面板。第二个样本框架，被称为新鲜样本，来自中央统计局2010年企业普查，由也门民意调查中心（YPC）提供更新和验证。

数据收集方式
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面对面 [f2f]

研究工具
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以下调查工具用于2013年也门ES：
- 制造业问卷；
- 服务问卷。

调查通过制造业或服务问卷进行，以避免向特定类型的企业提出无关问题，例如，不应向零售企业询问与生产和非生产工人相关的问题。除了询问跨国家的问题外，所有调查都是定制的，并包含针对特定国家的问卷。定制的例子包括在某些国家询问与旅游业相关的问题，因为旅游业是现有或潜在的经济增长部门。

使用制造业模块问卷（包括一组核心变量，以及制造业特定问题）对合格的制造业行业进行了调查。使用服务模块问卷覆盖了合格的服务机构。每个问卷变体的标识由索引变量a0确定。

所有变量均使用字母表中的每个部分的字母和该部分中变量的编号命名，例如，a1表示部分A，问题1。以前缀"MNA"开头的变量表示针对中东和北非地区的特定问题，因此它们可能不在其他国家推广实施中找到。所有其他后缀变量都是全球性的，并在世界各地的所有经济调查中都存在。所有变量都是数值型的，除非变量名称以"x