ACS table identifiers: B, C and other prefixes

ACS table identifiers encode information about a table's type and subject. The Census Bureau's Table IDs Explained page is the reference for interpreting that structure. The B prefix identifies a base Detailed Table. A C table is a collapsed table with less detail because some lines from its corresponding base table are grouped together. Other prefixes identify different products, including subject tables and profiles. A shared subject does not make the products interchangeable. Use a complete table identifier together with the release year and product. Do not use the prefix alone as a key, and do not discard suffixes when building a catalog. Start with the metadata for the actual release rather than assuming that a remembered title is sufficient. For a table lineage note, retain the exact identifier, published title, universe and line definitions from each edition. If a table disappears or changes, record the source evidence for the proposed replacement and describe any lost or added detail. The prefix is useful for orientation. It does not prove that a table has the same cells, universe or geographic availability in every year. Those questions require release-specific documentation.