Report series numbers are assigned by the originating agency or agencies, and represent the origin and status of the document. Report numbers may contain any or all of the following:
- the initial letters of the name of the issuing agency, such as DOE for Department of Energy
- an indication of the form of the document, such as TN for technical note or PR for progress report
- an indication of the status of the document, such as C for classified or S for secret
- the date of the report, such as 78/7 for July 1978
- the name of the project to which the report pertains
- an indication of the subject content of the report, such as H for health or LS for literature search
- a number indicating the series placement of the report
Examples of report numbers are:
NACA-WR-A-6 : 6th Wartime Report issued by the Ames Laboratory of the National Advisory Committee for Aeronautics
CONF-8410131 : the 131st conference report sponsored by an agency in October 1984
EPA 600/2-84-036 : the 36th report done in 1984 for the Environmental Protection Agency's environmental protection technology series
Contract numbers serve as an internal identification code to the contracting agency, and while sometimes cited, are not very useful. Contract numbers are not unique to one item, as several reports may have been generated from one contract. Examples of contract numbers are AT(29-2)-2831; DACW 72-74-c-0012; and NAS2-9410.
Clearinghouse accession numbers are either assigned by the sponsoring agency, in cases where the agency produces its own index, or assigned by the National Technical Information Service to the items it procures for sale. NTIS does not assign new accession numbers to reports it acquires from federal agencies that have assigned their own accession numbers.
Examples of clearinghouse accession numbers are:
AD : stands for ASTIA Document. ASTIA (Armed Services Technical Information Agency) is the former name of the Defense Technical Information Center (DTIC). Examples are AD 473920, and for more recent reports, AD-A 694219.
DE : numbers assigned by the Department of Energy (DOE). Examples are DE81016863 or DE84004926 where the first two digits indicate the year of the report.
N : numbers assigned by the National Aeronautics and Space Administration (NASA). Examples are N64-02345 or 94N23544, where the first two digits indicate the year of the report.
PB : stands for Publications Board. These accession numbers are assigned by NTIS, and were in one numerical sequence until 1980. Beginning with 1980, the indexing year is added to the sequential number. Examples are PB239580 and PB80-381264.