Enterprise Survey 2010 - Angola

Abstract
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The survey was conducted in Angola between June and November 2010 as part of the Africa Enterprise Survey 2010, an initiative of the World Bank. Data from 360 establishments were analyzed.

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. The mode of data collection is face-to-face interviews.

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 the universe, covered in the Enterprise Surveys is the non-agricultural private economy. It comprises: all manufacturing sectors according to the ISIC Revision 3.1 group classification (group D), construction sector (group F), services sector (groups G and H), and transport, storage, and communications sector (group I). Note that this population 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. Companies with 100% government ownership are not eligible to participate in the Enterprise Surveys.

Kind of data
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Sample survey data [ssd]

Sampling procedure
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The sample for Angola was selected using stratified random sampling. Three levels of stratification were used in this country: firm sector, firm size, and geographic region.

For industry stratification, universe was divided into one manufacturing industry, one service industry (retail), and one residual sector. The following sectors were included in the sample: manufacturing industry (ISIC codes 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 32, 33, 35, 36); retail (ISIC code 52); and services (ISIC codes 45, 50, 51, 55, 72).

Size stratification was defined following the standardized definition for the Enterprise Surveys: 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 a common practice, except in the sectors of construction and agriculture.

Regional stratification was defined by three regions (city and the surrounding business area): Benguela, Huambo, and Luanda.

For Angola, two sample frames were used.

The first frame was supplied by the World Bank. It consisted of enterprises interviewed in Angola in 2006. The World Bank requires that attempts should be made to re-interview establishments responding to the Angola 2006 survey where they were within the selected geographical regions and met eligibility criteria. Due to the fact that the previous round of surveys seemed to have utilized different stratification criteria (or no stratification at all) and due to the prevalence of small firm in the 2006 sample the following convention was used. To avoid oversampling smaller firms and to limit the presence of Panel firms to a maximum of 50% of the achieved interviews, a decision was made to restrict the number of issued firms with less than 20 employees. That sample is referred to as the Panel.

The second frame was produced by Dun & Bradstreet. A copy of that frames was sent to the TNS statistical team in London to select the establishments for interview.

The quality of the frame was assessed at the onset of the project through visits to a random subset of firms and local contractor knowledge. The sample frame was not immune from the typical problems found in establishment surveys: positive rates of non-eligibility, repetition, non-existent units, etc. In addition, the sample frame contains no telephone/fax numbers so the local contractor had to screen the contacts by visiting them. Due to response rate and ineligibility issues, additional sample had to be extracted by the World Bank in order to obtain enough eligible contacts and meet the sample targets.

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 3.55% (15 out of 422 establishments).

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

Research instrument
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The current survey instruments are available:
- 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]
- Screener Questionnaire.

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.” The survey is fielded via three instruments in order to not 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 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.

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 "Refusal to respond" (-8) as a different option from "Don't know" (-9).
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.

The number of contacted establishments per realized interview was 0.85. 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. This estimate is based on the total number of firms contacted, including ineligible establishments. The number of rejections per contact was 0.03.

Complete information regarding the sampling methodology, sample frame, weights, response rates, and implementation can be found in "Description of Angola Implementation" in "Technical Documents" folder.

摘要
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本调查于2010年6月至11月在安哥拉进行，作为世界银行发起的2010年非洲企业调查的一部分。分析了360个企业的数据。
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，以便能够追踪随时间推移的商业环境变化，从而允许进行例如改革影响评估。通过采访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，并创建了具有统计学意义且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、融资获取、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、土地和许可证、税收、非正式性、商业-政府关系、创新和技术以及绩效指标。超过90%的问题客观地确认了国家商业环境的特征。其余问题评估了调查受访者对阻碍企业增长和绩效的障碍的看法。数据收集方式为面对面访谈。
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实体。实体是指开展业务并进行工业运营或提供服务的地方。一个企业可能由一个或多个实体组成。例如，一个啤酒厂可能有几个灌装厂和几个分销实体。在本调查中，实体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。实体还必须拥有自己的管理和对其薪酬的控制。
总体
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企业调查所涵盖的总体，即整个总体，是非农业私营经济。它包括：根据ISIC修订版3.1分组分类（组D）的所有制造业部门、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，此人口定义不包括以下部门：金融中介（组J）、房地产业和租赁活动（组K，除子部门72，IT，该子部门已纳入研究人口），以及所有公共或公用事业部门。100%由政府拥有的公司无资格参加企业调查。
数据类型
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样本调查数据 [ssd]
抽样程序
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安哥拉的样本采用分层随机抽样方法选取。在该国使用了三个分层级别：企业部门、企业规模和地理区域。
在行业分层中，总体被划分为一个制造业部门、一个服务行业（零售）和一个剩余部门。样本包括以下部门：制造业部门（ISIC代码15、16、17、18、19、20、21、22、23、24、25、27、28、29、30、32、33、35、36）；零售（ISIC代码52）；和服务业（ISIC代码45、50、51、55、72）。
规模分层遵循企业调查的标准定义：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个适当的定义，因为季节性/临时/兼职就业在建筑和农业部门之外并不常见。
区域分层由三个区域（城市及其周边商业区）定义：本格拉、华姆波和罗安达。
对于安哥拉，使用了两个样本框架。
第一个框架由世界银行提供。它包括2006年在安哥拉接受采访的企业。世界银行要求，应尝试重新采访在选定地理区域内且符合资格标准的2006年安哥拉调查的实体。由于前一轮调查似乎使用了不同的分层标准（或根本没有分层）以及2006年样本中小企业的普遍存在，以下惯例被采用。为了避免过度抽样小型企业并将面板企业限制在达到的访谈数量的最大50%，决定限制发行少于20名员工的企业的数量。该样本被称为“面板”。
第二个框架由Dun & Bradstreet生成。该框架的副本被发送到伦敦的TNS统计团队以选择访谈的实体。
在项目开始时通过访问随机子集的企业和当地承包商的知识评估了框架的质量。样本框架并非没有在实体调查中发现的典型问题：非合格单位的正响应率、重复、不存在单位等。此外，样本框架不包含电话/传真号码，因此当地承包商必须通过访问他们来筛选联系。
由于响应率和资格问题，世界银行必须提取额外的样本，以获得足够的合格联系并达到样本目标。
考虑到样本总体中包含的非合格单位可能对结果产生的影响，在计算个别观察结果的适当权重时可能需要进行调整。已确认的非合格单位占调查接触到的总企业数量的3.55%（422个企业中的15个）。
数据收集方式
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面对面 [f2f]
研究工具
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当前调查工具可用:
- 核心问卷 + 制造业模块 [ISIC Rev.3.1: 15-37]
- 核心问卷 + 零售模块 [ISIC Rev.3.1: 52]
- 核心问卷 [ISIC Rev.3.1: 45, 50, 51, 55, 60-64, 72]
- 筛选问卷。
“核心问卷”是企业调查的核心，包含向全球所有企业提出的问题。还有另外两种调查工具——“核心问卷 + 制造业模块”和“核心问卷 + 零售模块”。调查通过三种工具进行，以避免向特定类型的企业提出无关的问题，例如，与生产和非生产工人相关的问题不应向零售企业提出。除了跨国家提出的问题外，所有调查都是定制的，并包含国家特定问题。定制的例子包括在某些国家当旅游业是现有或潜在的经济增长部门时询问与旅游业相关的问题。
标准企业调查主题包括企业特征、性别参与、融资获取、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、土地和许可证、税收、非正式性、商业-政府关系、创新和技术以及绩效指标。超过90%的问题客观地确认了国家商业环境的特征。其余问题评估了调查受访者对阻碍企业增长和绩效的障碍的看法。
清理操作
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承包商执行数据输入和质量控制，并将数据分批（通常为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、超出范围值、跳过模式和重复条目。问题由世界银行标记并由实施承包商通过数据检查、回调和重访实体进行纠正。
响应率
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调查的非响应必须与项目非响应区分开来。前者是指完全拒绝参与调查，而后者是指拒绝回答某些特定问题。企业调查受这两个问题的困扰，并使用了不同的策略来解决这些问题。
项目非响应通过以下两种策略解决：
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，调查员被指示收集“拒绝回答”(-8)作为与“不知道”(-9)不同的选项。
b- 在必要时，对信息不完整的企业进行重新联系以完成这些信息。
调查非响应通过最大程度地联系最初选定的访谈企业来解决。在建议替换企业（具有类似分层特征的）进行访谈之前，尝试在星期中的不同时间、不同日子联系该企业进行访谈。调查非响应确实发生了，但进行了替换，以有可能实现分层特定目标。
实现访谈的每个联系的企业数量为0.85。这个数字是两个因素的结果——反映在拒绝率（包括筛选和主要调查的拒绝）中的明确拒绝参与调查，以及由样本框架中不合格单位的存在代表的质量。这个估计是基于包括不合格企业的总企业联系数。每个联系的拒绝次数为0.03。
有关抽样方法、样本框架、权重、响应率和实施的完整信息可以在“技术文件”文件夹中的“安哥拉实施描述”中找到。