Census of Agriculture, 2007-2008 - El Salvador|农业普查数据集|农业生产数据集

Abstract
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The SIGE Technical Committee carried out an evaluation of the methodologies, procedures, processing and results of the IV Agricultural Census 2007 carried out by the Census Office of El Salvador of the Ministry of Economy and of the Multipurpose Surveys disseminated by the General Directorate of Agricultural Economics (DGEA) of the Ministry of Agriculture and Livestock, in order to identify the reasons that explain the significant discrepancies between its results and to make a proposal to the Consultative Committee on the officialization of the Census results.After the evaluation, the Technical Committee found that the results of the IV Agricultural Census were affected by difficulties and deficiencies in its implementation process, standing out among the most relevant ones:

i. The Census was carried out outside of the current institutional framework and did not have a broad inter-institutional committee (DGEA-Censuses), nor the support of a specialized external agency, such as the FAO, which would give neutrality and greater credibility to the process;

ii. The coverage of the census was affected by a high rate of omission of 10.9%, which was estimated by the project implementation team itself; nor was there a timely publicity campaign to reduce non-response;

iii. The quality of the census was negatively affected by the high turnover of staff who were unmotivated by inadequate treatment and salaries that did not compensate for the costs of staying in the rural areas of the interior of the country; this meant that the methodology staff invested excessive time in the successive training of new staff, neglecting monitoring tasks. These deficiencies were contrasted with the technical elements that made the Census process rigorous, and with the general characteristics of the design of the DGEA Surveys.

Geographic coverage
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National coverage

Analysis unit
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Households

Universe
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The statistical unit was the agricultural holding, an economic unit of production that carries out crop, livestock production or aquaculture activities, constituted of one or more plots located in the same municipality, and that can be managed by a person or a group of persons (civil or juridical). Three types of holdings were distinguished: holdings with (i) commercial producers; (ii) subsistence producers; or (iii) production obtained in gardens, aimed mainly for family consumption.

Kind of data
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Census/enumeration data [cen]

Sampling procedure
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i. Methodological modality for conducting the census
The classical approach was used for conducting the census.

ii. Frame
Prior to the census, a directory of large holdings was elaborated from administrative registers. A second list of agricultural holders living in urban areas was established, according to the information collected during the Population Census (PC) carried out in 2007 (the PC included a specific question about agricultural activities in the household). As a result, 22 509 agricultural households in 2 069 urban "segments" (PC) were listed.

iii. Complete and/or sample enumeration method(s)
The CA 2007/2008 combined complete enumeration and sampling. Rural areas (6 218 "segments") were canvassed and all segments were covered. Inside the segments, all commercial holdings were enumerated. Subsistence holdings and holdings with only backyard production were sampled at a rate of 20 percent (using systematic random sampling, or SRS). The holders to be interviewed were selected during the fieldwork by applying a filter form to all households in rural areas.

iv. Sample design
Given the small proportion of holders living in urban areas (estimated at less than 2.5 percent) the 6 208 urban "segments" from the recent PC were classified in two groups: 4 139 segments (66.7 percent) with no agricultural holder living in them and 2 069 with some holders, covering 22 509 agricultural households in urban areas. Four strata were defined;2 sampling rates of 20 percent, 30 percent, 100 percent and 8.5 percent respectively were applied to select the segments. Afterwards, the selected segments were canvassed and the filter form applied to every household in the segment. All households with commercial agriculture (in urban areas) were enumerated and households with subsistence agriculture or backyard production (in urban areas) were subsampled at a rate of 20 percent (using SRS).

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

Research instrument
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Four types of forms for data collection were used:

(i) listing form
(ii) listing quality control at segment level
(iii) commercial form
(iv) subsistence form

All 16 core items recommended by the WCA 2010 were included in the questionnaire for commercial holdings, which included specific sections dedicated to aquaculture, agricultural practices, manpower, livestock and food security. The core items are:

0001 Identification and location of agricultural holding
0002+ Legal status of agricultural holder
0003 Sex of agricultural holder
0004 Age of agricultural holder
0005 Household size
0006 Main purpose of production of the holding
0007 Area of holding according to land use types
0008 Total area of holding
0009 Land tenure types on the holding
0010 Presence of irrigation on the holding
0011 Types of temporary crops on the holding
0012 Types of permanent crops on the holding and whether in compact plantation
0013 Number of animals on the holding for each livestock type
0014 Presence of aquaculture on the holding
0015+ Presence of forest and other wooded land on the holding
0016 Other economic production activities of the holding's enterprise

Cleaning operations
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1. DATA PROCESSING AND ARCHIVING
Manual data entry was used for data capture.

2. CENSUS DATA QUALITY
A Post-enumeration Survey (PES) was conducted to assess the census quality. A systematic sample of 5 percent of census segments was taken. All segments in the sample were completely re-enumerated by means of a specific form. The rate of undercoverage was 10.9 percent. The comparison of census data with external data (such as estimates from MoA) showed that there were large discrepancies for several parameters. A special commission to reconcile the figures was formed in April 2009 and only partial results were delivered until the reconciliation had taken place.

摘要
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SIGE技术委员会对萨尔瓦多经济部和农业及畜牧业部下属的农业经济总局（DGEA）发布的2007年第四次农业普查的方法、程序、处理过程和结果进行了评估，旨在识别解释其结果之间显著差异的原因，并向咨询委员会提出将普查结果官方化的建议。评估后，技术委员会发现第四次农业普查的结果受到其实施过程中的困难和不足的影响，其中最相关的是：

i. 普查在现行机构框架之外进行，没有广泛的跨机构委员会（DGEA-普查），也没有像FAO这样的专业外部机构的支持，这将为过程带来中立性和更高的可信度；

ii. 普查的覆盖范围受到高达10.9%的遗漏率的负面影响，这一遗漏率由项目实施团队自行估计；同时，也没有及时开展宣传活动以减少非响应率；

iii. 普查的质量受到员工高流动率的负面影响，这些员工因待遇和薪酬不充分而缺乏动力，无法弥补他们在国家内地农村地区停留的成本；这意味着方法人员投入过多时间在连续培训新员工上，忽视了监督任务。这些不足与使普查过程严谨的技术要素以及DGEA调查设计的总体特征形成对比。

地理覆盖范围
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全国覆盖

分析单元
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家庭

总体
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统计单元为农业经营单位，这是一种生产经济单位，从事作物、畜牧业或水产养殖活动，由位于同一市镇的至少一个地块组成，并可由个人或一组人员（民事或法人）管理。区分了三种类型的经营单位：（i）商业生产者；（ii）自给自足生产者；（iii）在园地中获得的生产，主要用于家庭消费。

数据类型
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普查/人口普查数据 [cen]

抽样程序
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i. 普查的方法学模式

使用了经典的普查方法。

ii. 范围

在普查之前，根据行政登记编制了一个大型经营单位的目录。根据2007年人口普查（PC）期间收集的信息，建立了一个居住在城市地区的农业经营单位名单。结果，在2,069个城市“段”（PC）中列出了22,509个农业家庭。

iii. 完全和/或抽样登记方法

2007/2008年CA结合了完全登记和抽样。对农村地区（6,218个“段”）进行了调查，并覆盖了所有段。在段内，对所有商业经营单位进行了登记。自给自足经营单位和只有后院生产的经营单位以20%的比例进行了抽样（使用系统随机抽样，或SRS）。在实地工作中，通过将筛选表应用于农村地区的所有家庭来选择要采访的经营单位。

iv. 样本设计

由于居住在城市的经营单位比例很小（估计不到2.5%），因此将最近的人口普查中收集的6,208个城市“段”分为两组：4,139个段（66.7%）中没有农业经营单位，2,069个段有部分经营单位，覆盖了城市地区的22,509个农业家庭。定义了四个层次；分别应用了20%、30%、100%和8.5%的抽样率来选择段。然后，对选定的段进行调查，并将筛选表应用于该段内的每个家庭。对所有从事商业农业的家庭进行了登记，并将从事自给自足农业或后院生产的家庭以20%的比例进行了二次抽样（使用SRS）。

数据收集方式
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面对面 [f2f]

研究工具
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用于数据收集使用了四种类型的表格：

(i) 列表表

(ii) 段落级别的列表质量控制

(iii) 商业表

(iv) 自给自足表

商业经营单位的问卷中包含了WCA 2010推荐的所有16个核心项目，其中包含专门针对水产养殖、农业实践、人力、畜牧业和粮食安全的章节。核心项目包括：

0001 农业经营单位的识别和位置
0002+ 农业经营单位的法律地位
0003 农业经营单位的性别
0004 农业经营单位的年龄
0005 家庭规模
0006 经营单位生产的主要目的
0007 按照土地利用类型划分的经营单位面积
0008 经营单位总面积
0009 经营单位上的土地所有权类型
0010 经营单位上的灌溉情况
0011 经营单位上的临时作物类型
0012 经营单位上的永久作物类型及其是否为密集种植
0013 每种牲畜类型在经营单位上的牲畜数量
0014 经营单位上的水产养殖情况
0015+ 经营单位上的森林和其他林地情况
0016 经营单位企业的其他经济生产活动

清洗操作
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1. 数据处理和存档

使用了手动数据输入进行数据捕获。

2. 普查数据质量

进行了一次普查后调查（PES），以评估普查质量。从普查段中抽取了5%的系统样本。样本中的所有段都通过特定的表格进行了完全重新登记。覆盖不足率为10.9%。将普查数据与外部数据（如MoA的估计）进行比较，发现存在几个参数的大幅差异。2009年4月成立了一个特别委员会来协调数据，直到协调完成才提交了部分结果。