When a book in hand does not match a catalog record exactly, but does to some degree, it is necessary to decide when that record may be used and when a different one must be input. It was not unusual for staff to mistakenly use an available record created for a different edition in the past, particularly during the card catalog era. Compare fields 245 through 5xx for differences to justify a new record. Also see http://www.oclc.org/bibformats/en/input/default.shtm for more details, examples and many specific exceptions to the following general criteria.
· Variation in date designation associated with edition (e.g., Draft, Jan. 1989 vs. Draft, May 1989)
· Variation in numbered edition statements (e.g., 2nd ed. vs. 3rd ed.)
· Variation in statements indicating a difference in content (e.g., Teacher ed. vs. Student ed.)
· Variation in statements indicating abridgment, enlargement, etc.
· Variation in statements indicating "draft," "preliminary," "revision," etc.
· Variation in statements indicating geographic coverage (e.g., Midwest ed. vs. Western ed.)
· Variation in statements indicating language content (e.g., Spanish ed. vs. Italian ed.)
· Variation in description among issues of an edition that indicate a difference in content, e.g., illustrated vs. non-illustrated, certain sections present or absent, etc.