Step 3.2: Tag Flipping
MARS 2.0 can flip certain fields between each other during the authority matching process. Sometimes bibliographic records have been generated with information appearing in the wrong field. With Tag Flipping turned on, these fields can be set to match against different tags regardless of the information within the original field:
bib headings: 650 0 $a Italy (Rome) 650 0 $a European Union. match as tag (flip): 651 0 $a Italy (Rome) 610 20 $a European Union.* *the European Union flip will only happen if the optional 650-flip is added
If the authority record causes the tag flip (difference in usage between 1XX and 4XX), then tags will always be flipped regardless of any other rule. Tag flipping rules excludes X50 to X00 flipping.
The rule that only subjects can flip to/from X50 and X51 also applies here. The MARS 2.0 Auxilliary File will not be included in this rule.
Tag flipping rules
If Tag Flipping is marked, then the following rules apply:
- If 100, 110, 111, 700, 710, 711 matches X51 (authority) and the bib tag 1st indicator is 1, and the field only contains $a, then the tag is forced to X10
- If $a contains a single word or initials, no flip is allowed between X00 and X10
- Only subjects can flip to X50 or X51 based on an authority match:
- If the bib tag is 600 or 611, flip to a 610
- If the bib tag is 610 and is only $a or is $a and the second subfield is $v, $x, $y, $z then the bib heading can be flipped
- If the bib tag is 610 and it contains other subfields than above, it will not be allowed to flip
- Tags X50 and X51 can flip between each other
- Tags can never* flip from X51, except X50
- Tags can never* flip to or from 655
- Tags can never* flip to or from X30 unless the authority record causes the tag flip
- Tags will never* flip from matches to 18X subdivision authority records
- Any flips not explicitly included above are allowed: X00, X10, X11 can flip between themselves
Note: A Possible Invalid Tags report (see Step 5.2, R09) includes headings in which MARS 2.0 was programmed not to flip the tag, even though the tags in the bibliographic and authority records did match.
For example, a 130 tag is never flipped to a 100; similarly, a 710 is never allowed to flip to a 651. The Tags Flipped report (see Step 5.2, R32) includes tags that were changed during automated processing.
*Never say never in these rules, as we can also create a custom match rule that would allow these particular flips, upon request.
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