Data item descriptions

A United States data item description (DID) is a completed document defining the data deliverables required of a United States Department of Defense contractor. A DID specifically defines the data content, format, and intended use of the data with a primary objective of achieving standardization objectives by the U.S. Department of Defense. The content and format requirements for DIDs are defined within MIL-STD-963, Data Item Descriptions (1997).

The terminology of DIDs and the term contract data requirements list (CDRL) originated with US military procurements, and it is now often encountered in other large procurements that are modeled after the military procurement process. Within a military solicitation or contract, each DID is uniquely numbered to identify the data deliverables in terms of specific information such as: purpose, description, preparation instructions including a table of contents and descriptions of each section, and references to the Contract Statement of work (SOW).

Practices and terms where definition is given by MIL-STD-963:

Since DID documents are what contract mechanics cause to be produced, the defined content guidelines and their terminologies are commonly referred to in United States Military Standards or other forms of procedural and administrative guidance of the United States Department of Defense.

Writers of a SOW often include requirements that belong in other parts of a contract. Specifically, quantitative technical requirements are addressed in the military specification and work requirements are specified in the SOW, and data requirements (e.g., delivery, format, and content) should be in the CDRL along with the appropriate DID to minimize the potential for conflict.

...
Wikipedia