The purpose of this crosscheck is to make sure that a large print record does not match a similar record for a non-large print item. To do this, we look at a very large number of fields and attempt to answer the question: Does this record represent a large-print item (True or False)?
The extracted data is checked, in the order listed above, for any occurrence of the word 'LARGE' followed by either of the words 'PRINT' or 'TYPE'. If this phrase is found, then the large print flag for the record is set to True.
If the above logic fails, several well-known large print publisher strings–'CHIVERS', 'THORNDYKE', 'ULVERSCROFT'–are matched against the 260 $b, and if found, the large print flag for the record is set to True.
If both records represent large print items, or neither record represent a large print item, the crosscheck passes.