Improving retrieval of microform set records: Updating 008 dates and for records cataloged prior to 991

A change in USMARC coding in bibliographic records for reproductions was im plemented in 1991, and that change created inconsistencies between post-199 1 major micro-form record sets and ones already existing in library catalog s. Because retrieval and display in OPACs may depend on Date 1 in USMARC fi eld 008, this particular inconsistency has become more apparent and trouble some as records with newer coding have been added to catalogs containing re cords with older coding. Libraries have several choices in preserving their investment in the pre-1991 records. One way is automated editing of the re cords. We describe one method using Visual Basic.