Most fixed fields in authority records are either constants or are system supplied.  The only fixed fields catalogers will routinely need to determine are:

Descriptive cataloging code (008/10)

code a for earlier rules (not used for newly created NARs)

code b for AACR1 (not used for newly created NARs)

code c for AACR2

code d for AACR2-compatible headings (used only for a newly established NAR for a uniform title entered under a personal or corporate name that is already coded d, or for a subordinate unit entered under a corporate name already coded d)

Undifferentiated personal name (008/32)

code a for a differentiated (i.e.,representing one person) personal name or a name-title entered under a personal name

code b for an undifferentiated (non-unique) personal name (i.e., a name heading that represents more than one person with the same name, according to AACR2 22.20)

code n otherwise (i.e., for a corporate, conference or geographic name)

Reference evaluation (008/29)

code a if the record includes cross references (4XX or 5XX)

code b for unevaluated references that must be revised if record is being updated; do not use in newly-created records

code n if there are no cross references

Level of establishment (008/33)

code a for full-level

code c for provisional level

code d for preliminary level

See also:

Section I:  New Authority Records