U.S. Department of Commerce

USA Counties Data File Information

Windows XP File Download Setting
Basic Information
Basic Information on Mastgroups File
Basic Information on Mastdata File
Locating the Correct Data File
Locating Corresponding Columns Associating with Selected Item_Id
Data Type Applied
File Formats:
Mastgroups File Format
Mastdata File Format
Unit_Reference Format
Source Format
Footnote Reference
Flag Reference
Appendix A - Source Notes and Explanations
Questions or Additional Information

Windows XP File Download Setting

  1. Double-Click My Computer icon
  2. Select Tools from Windows Toolbar
  3. Select Folder Options...
  4. Select File Types Tab
  5. Under Registered File Types, select XLS Microsoft Excel
  6. Click Advanced button
  7. Make sure the Confirm open after download box is checked
  8. Click OK button
  9. Click Close button

Basic Information

1) Mastgroups - (KeyAbr and KeyAbreviation)

Open Excel file Mastgroups. It will have two columns KeyAbr and Descript. In column KeyAbr, the user will find a standard three character abbreviation or acronymn for its official title as listed under Descript. Try to become familiar with the three character abbreviation or acronymn being used.

Example:
If a user is interested in the descript of Agriculture - NAICS then they should write down or become familiar with the abbreviation or acronymn of AGN. This will come into play when the user next opens the Mastdata file.


2) Mastdata - (Item_id and Item_Description)

Next, open file Mastdata. This Excel file has two columns with column names of Item_id and Item_description (row 1).

Column Item_id provides a name of an Excel column, for example, AFN110197D. The AFN of AFN110197D indicates this is AFN type data. The 110 of AFN110197D indicates the group-series number of AFN data. The 197 of AFN110197D indicates this is data of the year 1997, and D stands for data. Likewise, 202 of AFN110202D indicates this is data of the year 2002.

The user should examine the titles in column Item_description and locate the description they are looking for. Once a user locates an Item_description they are looking for, make note of the Item_id corresponding to that Item_description. That Item_id is column name the user will be looking for in one of the actual Excel data files.


3) Locating the Correct Data File, with selected data columns

Example:
If a user is interested in file AGE110197D, they examine Excel files AGE01.xls, AGE02.xls, or AGE03.xls, or they may use zip file AGE.zip. The columns of files AGE01.xls, AGE02.xls, and AGE03.xls are listed in alphabetical order. For example, for AGE series, the columns would range from AGE010180D to AGE430202D in AGE01, AGE430203D to AGE830205D in AGE02, and AGE830206D to AGE900206D in AGE03. Therefore, column AGE110197D would be located in the AGE010180D to AGE430202D range, which can be found in files AGE01.xls orAGE.zip.

Note that sum topics only have one related file, and some may have 2,3,4 or more files related to the key topic. The example above in reference to AGE has three files AGE01, AGE02, or AGE03.


4) Locating the Corresponding Columns of the Selected Item_id

Every data file, e.g. AGE01, AGE02, or AGE03, has its first two columns as Areaname and STCOU. STCOU stands for the State-County code of a specific region (county, state, federal). Each Item_id, e.g., AFN110197D has four columns (flag, data values, footkey1, footkey2). The name ending with F is the flag column of the selected Item_id, for example, AFN110197F. The name ending with D is the datavalue column of the selected Item_id, i.e., AFN110197D. The name ending with N1 is the Footnote1 column of the selected Item_id, i.e., AFN110197N1. The name ending with N2 is the Footnote2 column of the selected Item_id, i.e., AFN110197N2.

Example:
Each table selected (Item_id) has four corresponding columns of data: flag, datavalue,
footkey1, footkey2 e.g. AFN110197F, AFN110197D, AFN110197N1, and AFN110197N2.


5) Data type

Moreover, the flag column of a selected Item_id is integer data and the datavalue column of a selected Item_id is double (numeric) data. The Footkey1 and Footkey2 columns of a selected Item_id are text data. The STCOU column is text data, and the Areaname column is text data.


File Formats

Mastgroups File Format - the generalized group classification of data
Subject: Field Name: Description:
Field 1: KeyAbr (text data) Acronym for Mastgroup title in DESCRIPT field, e.g. acronym HEA stands for Health
Field 2: DESCRIPT (text data) Name of a specific group of data e.g. Health is a group, where there may be many individual Health files (Excel columns)
Mastdata File Format - collection of all individual data names (originally a table name) and description
Subject: Field Name: Description:
Field 1: Item_Id (text data) Official name of data subject (e.g. AFN110197D has four parts: mastgroup, file number, year of data, and D. In this case the mastgroup is AFN and the file number is 110. The year is 197 which stands for 1997 and is followed by the letter D)
Field 2: Item_Description (text data) Detail description of name under Item_Id
Unit_Reference File Format - units of measurement applied to data of individual data collections
Subject: Field Name: Description:
Field 1: ID (text data) Acronym for Unit Description
Field 2: DESCRIPT Units in reference to data value
Source File Format - source provider of data
Subject: Field Name: Description:
Field 1: ID (text data) Acronym for Description (Data Provider)
Field 2: DESCRIPTION (text data) Name of data provider
Footnote_Reference File Format - collection of footnotes applied to some records of each data collection
Subject: Field Name: Description:
Field 1: ID (text data) Four digit footnote code
Field 2: DESCRIPTION (text data) Detail description corresponding to footnote code
Flag_Reference File Forma - reference description and id of applied flags used in data collection
Subject: Field Name: Description:
Field 1: ID (text data) Id of a particular flag_reference
Field 2: DESCRIPTION (text data) Detail description of a particular flag reference

Appendix A: Source Notes and Explanations

For comments on data quality, see Appendix A - Source Notes and Explanations [PDF, 203KB] from the 2007 edition of the country and City Data Book


Questions or Additional Information

For further information visit https://ask.census.gov

Source: U.S. Census Bureau

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