One of the keys to using these large datasets is knowing what tables are available and within these tables what do each of the data cells represent. For this we have created yet another subdirectory called Varlabs (within the basetbls subdirectory. There are (usually) 8 files within these metadata collections. Two are small and trivial but very useful: TableTopicCodes.txt contains this:
The first 2 digits of a base table number are the topic code. So
if you are looking for tables related to poverty (for example) you need
look only at tables B17xxx and C17xxx . These tables would be found in
a data set such as ustabs17_203yr (3-year period estimates with all
tables in topic 17 through 20.) The "Topic Group" is part of the data set
Topic Group 00_07: Basic Demographics and Ancestry
00 = Unweighted sample counts.
01 = Age and Sex
02 = Race
03 = Hispanic or Latino Origin
04 = Ancestry
05 = Foreign Born, Citizenship
06 = Place of Birth
07 = Residence Last Year, Migration
Topic Group 08: Journey to Work
08 = Journey to Work, Worker Characteristics
Topic Group 09_16: Households, Families, Misc. Social Characteristics
09 = Children, Relationship
10 = Grandparents, Age of HH members
11 = Households, Families
12 = Marital status
13 = Fertility
14 = School enrollment
15 = Educational attainment
16 = Language spoken at home
Topic Group 17_20: Income and Poverty
17 = Poverty
18 = Disability
19 = Income (Household, family)
20 = Earnings (Individuals)
Topic Group 21_24: Employment and Related Items
21 = Veteran status
22 = Transfer Programs, Food Stamps
23 = Employment status
24 = Industry, Occupation, Class of Worker
Topic Group 25_27: Housing, Group Quarters and Insurance Coverage
25 = Housing Characteristics
26 = Group Quarters
27 = Insurance Coverage (collected only since 2008, N.A. on 2007-2011 5-year data)
28 = Computer Ownership and Internet Use
Topic Group 99: Imputation (NA on this site)
99 = Imputation tables.
The remaining 6 Varlabs files have names with familiar numeric suffixes. The file
the critical metadata for anyone wanting to know what data are contained in a dataset with 17_20 in its name.
These are simple text files that can be quickly loaded into your browser and viewed, searched or printed.
The exact details of what appears in these files has varied slightly over time but the gist of them has remained the same.
You get the table title and universe followed by "detail lines" describing each cell within the table. For example:
Base (summary) table names are comprised of a letter (B or C), a 5-digit code (the first 2 of which constitute
the topic code), and (sometimes) an alpha suffix (to indicate a special race/hispanic universe (per the
BaseTableAlphaSuffixes.txt, shown above). There can also be a "PR" suffix to indicate a file available only for
Puerto Rico. We do not include PR tables in these metadata files.
We now keep only one set of Varlabs metadata files, even though the available tables for a given vintage can
vary with the single year vs. five year files. We handle this by including the special comment line:
Similarly, starting with the 2015 vintage data (and we may go back and update earlier versions) we also display
a similar comment to identify tables that are not available at the block group level on the 5-year files.