American Community Survey 2009-2013 ACS 5-Year PUMS File

The Public Use Microdata Sample (PUMS) contains a sample of actual responses to the American Community Survey (ACS). The PUMS dataset includes variables for nearly every question on the survey, as well as many new variables that were derived after the fact from multiple survey responses (such as poverty status). Each record in the file represents a single person, or--in the household-level dataset--a single housing unit. In the person-level file, individuals are organized into households, making possible the study of people within the contexts of their families and other household members. PUMS files for an individual year, such as 2013, contain records of data from approximately one percent of the United States population. As such, PUMS files covering a five-year period, such as 2009-2013, contain records of data from approximately five percent of the United States population.<br><br>The PUMS files are much more flexible than the aggregate data available on American FactFinder, though the PUMS also tend to be more complicated to use. Working with PUMS data generally involves downloading large datasets onto a local computer and analyzing the data using statistical software such as R, SPSS, Stata, or SAS.<br><br>Since all ACS responses are strictly confidential, many variables in the PUMS file have been modified in order to protect the confidentiality of survey respondents. For instance, particularly high incomes are "top-coded," uncommon birthplace or ancestry responses are grouped into broader categories, and the PUMS file provides a very limited set of geographic variables.<br><br>***<br>Microdata: Yes<br>Level of Analysis: Individual - person, household<br>Variables Present: Separate Document<br>File Layout: .xlxs<br>Codebook: Yes - pdf<br>Methods: Partial<br>Weights (with appropriate documentation): Yes<br>Publications: No<br>Aggregate Data: No<br><br>

公共使用微数据样本（Public Use Microdata Sample，PUMS）收录美国社区调查（American Community Survey，ACS）的实际调研应答抽样数据。PUMS数据集涵盖该调查中几乎所有问题对应的变量，同时包含诸多事后基于多份调研应答推导得到的新变量（如贫困状况变量）。文件内的每条记录分别代表单个个人；若为家庭层面数据集，则代表单个住房单元。在个人层面文件中，个体按家庭进行分组，这使得研究者能够在家庭及其他家庭成员的背景下开展个体研究。单年度的PUMS文件（如2013年版）包含约占美国总人口1%的样本数据。同理，覆盖五年周期（如2009-2013年）的PUMS文件，则包含约占美国总人口5%的样本数据。

相较于美国事实查询器（American FactFinder）平台上可获取的汇总统计数据，PUMS文件具备更强的灵活性，但同时其使用复杂度也相对更高。使用PUMS数据通常需要将大型数据集下载至本地计算机，并借助R、SPSS、Stata或SAS等统计软件开展数据分析。

由于所有ACS调研应答均受到严格保密，PUMS文件中的诸多变量已进行脱敏修改，以保护受访者的隐私。例如，过高的收入数据会进行最高编码（top-coded）处理，罕见的出生地或血统应答会被合并至更宽泛的类别中，且PUMS文件仅提供极为有限的地理变量集。

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微数据：是
分析层级：个体——个人、家庭
所含变量：详见单独文档
文件格式：.xlxs
代码手册：是——PDF格式
分析方法：部分可用
权重（附完整说明文档）：是
可引用出版物：无
汇总数据：无