Content of data elements:

The content of the data elements that comprise a USMARC record is usually defined by sources outside the formats such as the Library of Congress Classification (LCC), the Dewey Decimal Classification (DDC) or other classification schemes used by the organization that creates a record.

The content of certain coded data elements is defined in the USMARC formats (e.g., the Leader , field 008 , subfield $w in the 4XX and 5XX tracing fields ).