Dedupe 2.0

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Dedupe 2.0: Group 1

Section 2.0 of the dedupe profile deals with the 010, 020, 022 field hits & subsequent verification criteria. These fields are typically considered to be more reliable within the bibliographic record than other fields such as the 245 (Title). Due to this, you may consider relaxing some of the verification points depending on how much trust you put into the cataloging integrity of these particular fields within your records.

Group 1 Hit Fields

Grouping allows the user to have different parameters for different potential matches. Since numeric fields such as the LCCN, ISBN, and ISSN are fairly reliable in most cases, they are grouped together and will have the same verification parameters.

010 - LCCN

The Library of Congress Control Number (LCCN) assigned to a catalogued item is recorded in the 010 tag. This number is used to to distinguish each record from every other record in the database Library of Congress database.

The LCCN has three parts: the prefix, a year (represented by two or four digits) and a serial number (six digits) followed by another space in the case of pre-2001 LCCNs. Suffixes and revision dates following some printed LCCNs may or may-not be keyed into MARC record.

The following subfields are valid in the 010 tag:

  • a - LC control number
  • b - NUCMC control number -- This subfield is used only in archival/manuscripts format
  • z - Cancelled/invalid LC control number
 010 $a   91001938 
 010 $a  2001012884
 010 $a   08000123 $z   80000123 

020 - ISBN

This field records the International Standard Book Number(s) (ISBN) assigned to a catalogued item. Each valid ISBN is entered in a separate 020 tag; two or more invalid or cancelled ISBNs may be recorded in a single 020 tag.

The following subfields are valid in the 020 tag:

  • a - International Standard Book Number
  • c - Terms of availability
  • z - Cancelled/invalid ISBN

Valid ISBNs are always 10 or 13 digits long; all ISBNs are assumed valid unless they have too many or too few digits, or unless a shelflist card specifically identifies an ISBN as cancelled or invalid:

 020 $a 0049812187
 020 $a 9780049853217

The only letter that is ever part of an ISBN is X (roman numeral 10); it must always be capitalized:

 020 $a 012817409X

Subfield $a may contain qualifying information (publisher, binding, format, volume numbers). This information is usually entered within parentheses; separate pieces of information with space-colon-space:

 020 $a 001281947X (pbk.)
 020 $a 0018942113 (Bally Bros. : pbk.)
 020 $a 0137183911 (large print)

Prices appearing after ISBNs are catalogued in subfield $c:

 020 $a 0174620684 :$c $21.95
 020 $a 0049812187 (pbk.) :$c $17.40

022 - ISSN

An International Standard Serial Number (ISSN) is an identification number assigned to a serial (the entire serial, not just a particular issue). The ISSN is similar in function to the ISBN assigned to books. The 022 tag is repeated whenever a serial has two or more valid ISSNs. This sometimes happens when a serial changes its title and a new ISSN is assigned; when a record is created for the new title, both the new and the old ISSNs (both still valid) are entered in the new record.

The following subfields are valid in the 022 tag:

  • a - International Standard Serial Number
  • l - ISSN-L
  • m - Cancelled ISSN-L
  • y - Incorrect ISSN
  • z - Cancelled ISSN

This field only contains digits except the last digit may be X (roman numeral 10):

 022 $a 1234-5678
 022 $a 9876-123X

Subfield l links together various media versions of a continuing resource:

 022 $a 1234-5678 $l 1234-1231

Group 1 - Verification Criteria and Terms

The Verify criteria is used to reduce the number of initial matches found using the Hit criteria. This allows you to further define what constitutes a good match based on the existence of other fields within your records. Fields should be selected on the basis of the match-rate you expect to see with the deduplication. Selecting fewer fields will result in more matches; selecting more fields will result in fewer, but better matches. Verify criteria should also be selected in conjunction with Hit criteria.


There are a few methods for verifying: FULL, PARTIAL, and WITHIN. These methods will be used for comparing data found in a specific field against the same field in a potential match record.


Full compares the entire verify string up to the verify length.


Partial truncates the compare strings to the shortest string, then does a full compare:

 Record A:
   The fox and the hound.
 Record B:
   The fox.
 Both are truncated to The fox and compared.


Within searches each compare string truncated at verify length against the full un-truncated string of the other field:

 Record A:
 Record B:
   The cat in the hat.
 Cat in Record A will verify against The cat in the hat in Record B.


Normalization refers to how the string will be presented when compared to another string. Note that any normalization will not change anything in the record, but is only used when the program compares the strings.

Types of normalization are:

  • NACO/CJK - retains spaces and subfield delimiters
  • FULL - all spaces and subfield delimiters removed
 original field:
   $a Daniel Boone :$b a pioneer.
 normalized (naco/cjk):
 normalized (full):

Length & Words

This refers to how much of a given string the program will present for potential matches:

  • Length - Refers to the number of characters for the verify field. The number of characters to be used is 1-2048, or all. Using a length of 10 gives us this example:
 original heading:
   $a Daniel Boone :$b a pioneer.
 normalized (full), length = 10:
  • Words - Refers to a count of words to match within a given string:
 original heading:
   $a Daniel Boone :$b a pioneer.
 words = 2:
   Daniel, Boone, A, or Pioneer are all possibilities for keyword matching.

NOTE: Non-filers are excluded from Words.

Must Verify

This option requires the given field to match between the two records. It also means that the verify field in question must exist in both records (and must match). This is typically common to include as part of the 245 title verification, though other fields may find it useful as well.

Only if Both

This only does a verify comparison if both records have a specified field; verifies as true if only one of the records has the field. If this option was used on the 1xx field, the following would be true: Example 1:

 Record A has:
   100 $a Twain, Mark.
   245 $a Adventures of Huckleberry Finn.
 Record B has no 100
   245 $a Adventures of Huckleberry Finn.

RESULT: This would be a match because the 100 exists in one but not the other.

However, when two records each have their own 1XX field and they differ, we have this scenario:

 Record A has:
   100 $a Twain, Mark.
   245 $a Adventures of Huckleberry Finn.
 Record B has:
   100 $a Clemens, Samuel.
   245 $a Adventures of Huckleberry Finn.

RESULT: This would not be a match because the 100 differs.


Group 1 - Hit Criteria

Group 1 - Verify Criteria


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