Once you have found a record that you think might match the resource that you are to describe, your next step is to be certain that this is indeed the case.

As you match a record to a resource:

• Keep these RDA principles in mind:
  • 0.4.3.1 Differentiation, i.e., the data that we provide about a resource, should be enough to allow a user to tell the difference between similar resources. Therefore:
    • if data is present or applicable to your resource and is absent from a record that you have found, then that record might not match your resource; equally
    • if data is absent or not applicable to your resource and is present in the record, then that record might not match your resource
  • 0.4.3.4 Representation, i.e., the data that we provide about a resource, should mirror what is on the resource as closely as possible (put down what you see). Therefore, if the transcribed data in a record does not mirror the data on the resource being described, then that record might not match your resource.

• Remember to check every element on the appropriate Match Table (Books, eBooks, Videos, etc.) Don't just check the elements that are present in a record; check for elements that are missing, because sometimes the fact that element data is present on the resource and is missing in the record (or vice versa) indicates a difference.

Use the Match Table below that is appropriate for the resource:

Matching Table: Book (Very brief)

Matching Table: Book (Brief)

Matching Table: Book (Full)

Matching Table: eBook

Matching Table: Sound

Matching Table: eSound

Matching Table: Video

Matching Table: eVideo

For each element on the Tables above:

• Check the 'Source' instruction to be sure that you are looking at the correct source(s) of information on the resource for the data:
  • the data for most Identifying elements are copied from the resource itself
  • the data for all Carrier elements are determined, primarily, by looking at the resource itself
  • the data for all Content elements can come from any sources
  • the data for all Relationship elements can also come from any sources

• Then determine which of the conditions below applies to the data for each element on the table and follow the matching instruction in the appropriate column for the element (click the instruction for more details):
  • is the data:
    • PoR/PaE: present on, or applicable to the resource and present as an element in the record
    • PoR/AaE: present on, or applicable to the resource but absent as an element in the record
    • AoR/PaE: absent on, or not applicable to the resource, but present as an element in the record
    • AoR/AaE: absent on, or not applicable to the resource, and absent as an element in the record

• If data is present on, or applicable to the resource and/or is present as an element in the record and is not on a matching table, find that element in the Matching Elements (All) index and follow the instructions provided for it.

• When data is present as an element in a record, if it is:
  • transcribed: it must match exactly, word-for-word, letter-for-letter, what is present on the source of information (except for exceptions)
  • recorded: it must be appropriate for the resource

• When data is present on or applicable to the resource, but is absent as an element in the record, you must determine whether that data is absent as an element because that data:
  • was not present on or applicable to the resource that the record is describing, and therefore that resource is not the same as the resource that you have
  • is not core, and so was simply not entered by the other cataloger
  • was missed by the other cataloger

• If a record is CIP or Pre-Pub (Encoding level: '8' '3' or 'M') then remember that –anything- might have changed between the publisher sending data to the agency that made the CIP/Pre-Pub record and the actual publication of the resource; so be much more forgiving of differences in the data that is present on, or applicable to the resource and the data that is present as an element in a CIP/Pre-Pub record.

• As you go through the table, if an element is OK for matching, then move on to the next element, to the end of the table. If any of the elements on the table are not OK, then you need a new record; even if you copy a nearly matching record to make into a new record, remember that it is still a NEW record

• 'MARC' column:
  • codes remind you about the elements that you must check for matching when working with a MARC record; they are organized in (mostly) MARC order
  • links take you to the appropriate page of matching instructions for the element
• 'RDA Element' column:
  • element names tell you the RDA elements that you should check for matching
  • links take you to the appropriate page of matching instructions for the element
• 'Source' column:
  • abbreviations and terms give you a quick reminder about where to look for the data of the RDA element, so that you can be sure that you are looking for data from the same source on the resource that was used for the data in the record (if the record was cataloged according to the same source instructions that you are following)
  • links take you to explanations for the abbreviations and terms, from the definitions page
• 'PoR/PaE' and adjacent 'Data Entry Matching' columns give you a quick reminder about the matching instructions for each RDA element, to help you to decide whether the data for the element is a match or no match, when the data is Present on the Resource/Present as an Element in the record
  • links for the 'PoR/PaE' column take you to an explanation for the abbreviations, from the definitions page
  • links for the 'Data Entry Matching' column take you to the appropriate page of matching instructions for the element
• 'PoR/AaE' and adjacent 'Core Matching' columns give you a quick reminder about the matching instructions for each RDA element, to help you to decide whether the data for the element is a match or no match, when the data is Present on the Resource/Absent as an Element in the record
  • links for the 'PoR/AaE' column take you to an explanation for the abbreviations, from the definitions page
  • links for the 'Core Matching' column take you to the appropriate page of matching instructions for the element
• 'AoR/PaE' and adjacent 'Source Matching' columns give you a quick reminder about the matching instructions for each RDA element, to help you to decide whether the data for the element is a match or no match, when the data is Absent on the Resource/Present as an Element in the record
  • links for the 'AoR/PaE' column take you to an explanation for the abbreviations, from the definitions page
  • links for the 'Source Matching' column take you to the appropriate page of matching instructions for the element
• 'Function' column reminds you whether the function of the data is for Identification, etc. The Iden (Identifying) elements and Cont (Content) elements are the most important for matching, and you only need to check Rel (Relationship) elements when data for those elements is not already given in the record as another identifying element or content element
  • links take you to explanations for the abbreviations, from the definitions page
• 'Entity' column for an element reminds you about the entity level that the element applies to: 'M' = Manifestation; 'W' = Work; 'E' = Expression

For each element on the Matching table, keep these fundamental instructions in mind:

• Core (data must be provided if it is applicable and readily ascertainable)
  • if an element is core for RDA and is present on the resource and is absent from the record, that should mean that the record does not match the resource (except for error)
  • if an element is not core for RDA, or is only core if something else is missing, or is only partially core, and is present on the resource and not present in the record, that could mean that the record does not match the resource, or it could mean that the other cataloger decided not to add the data, since it was not core.

• Source
  • when matching data, always look for it on a resource from the assigned source(s) of information for the element, and in the preferred order for those sources; remember that RDA has expanded the places that we can look for element data, but we must always get the data from sources in the preferred order; e.g., SSaPubN / ASWR / [OSoI] means: begin looking for data on the same source as the publisher's name, then, if it is not there, try another source within the resource itself, then, if it is not there, provide supplied data from the specified 'other sources of information'.

• Data Entry
  • when matching data, remember that it should have been entered as instructed by RDA; so, if the data is supposed to be:
    • Transcribed: remember the RDA principle of representation, which means that the data should match what is on the resource, word-for-word, letter-for-letter, except for exceptions (e.g., 1.7 and 1.8), and sometimes differences in order and optional omissions
    • recorded from a vocabulary: the data should be appropriate to the resource even if it is not a term from the official RDA the list for the element
    • Recorded as a note: the data should be appropriate to the resource
    • Recorded as a relationship: the relationship should be appropriate for the resource, but remember that a relationship can be added even though that relationship might not be mentioned on the resource itself

• MARC coding
  • MARC coding and ISBD punctuation does not matter for matching.

The resource and agent elements in RDA are grouped into categories, and understanding those groupings can help you to see patterns in the instructions, which can help you decide how to match data for the elements:

• Element Groups for Resources
• Element Groups for Agents

There are patterns in the instructions for entering particular types of data, and understanding these patterns can help you to remember how to match data:

• Entering Transcribed Data
• Entering Vocabulary Data
• Entering Recorded Data
• Entering Authorized Access Points
• Entering MARC Data

See the table at this link for some additional patterns to be found in the most common elements in RDA records.

The criteria for matching records and resources, outlined below, are based on the following AACR-based guidelines on when to make a new record. These guidelines have not, yet, been updated to include new MARC fields, added to accomodate RDA, so I have had to extrapolate some of my guidelines without any official guidance:

• “When to Input a New Record” in OCLC Bibliographic Formats and Standards. 4th ed. 2008. Online document. November 19, 2008
• Differences Between, Changes Within. 2007. Chicago: Association for Library Collections & Technical Services.

The only RDA Toolkit guidance that I could find for deciding on a 'new edition' is the LC-PCC PS for 2.1, under “Edition or Copy of Book”.