Profile Guide Step 3.3

MARS 2.0 programs 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.

Step 3.3 Question

With Tag Flipping turned on, these fields can be set to match against different tags regardless of the information within the original field:

Example
	Bibliographic heading:
	650   0	$aItaly (Rome)
	650   0	$aEuropean Union.

	Match as tag (flip)
	651   0	$aItaly (Rome)
	610  20	$aEuropean Union.

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—unless “Do Not Flip” is selected. The rule that only subjects can flip to/from X50 and X51 also applies here. The MARS 2.0 Auxiliary File will not be included in this rule.

Tag Flipping Rules

If Tag Flipping is marked, then the following rules apply:

1. Matches to subdivision records (18X) will never cause a tag flip
2. Tags can never flip to or from 655
3. Tags can never flip to or from X30 unless the authority record causes the tag flip
4. If a 100, 110, 111 or a 700, 710, 711 matches an X51 and the bib tag first indicator is ‘1’, and the field only contains $a, then the tag is forced to X10
5. Only subjects can flip to X51 based on an authority match:
   1. If the bib field is 600 or 611, flip to a 610
   2. If the bib field is 610 and is only $a or is $a and the second subfield is $v, $x, $y or $z then the bib heading can be flipped
   3. If the bib field is 610 and it contains other subfields than above, it will not be allowed to flip
6. Tags X50 and X51 can flip between each other
7. No tag will ever flip from X51 to another usage (except X50)
8. Only subjects can flip to X50 based on an authority match
9. Flips are allowed from X50 to X00, X10, X11 in subject fields
10. If $a contains a single word or initials, no flip between X00 and X10 is allowed
11. Any flips not explicitly included above are allowed (X00, X10, X11 can flip among themselves)

Note: An R09 (Step 5) report includes headings in which MARS 2.0 programs were 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 R32 report includes tags that were changed during automated processing.