Better Online Citations – Details Part 5 (MODS)

Monday, 22 Jun 2009 | by Mark Tucker


In this post, we continue our exploration through existing bibliographic standards to see how they might work as a format for online sites to easily share citation information.  To see the journey we have made so far, visit the page, A Better Way to Cite Online Sources.

From the Library of Congress standards page for MODS, we see the following description:

Metadata Object Description Schema (MODS) is a schema for a bibliographic element set that may be used for a variety of purposes, and particularly for library applications.

On the MODS overview page, we get more details:

As an XML schema it is intended to be able to carry selected data from existing MARC 21 records as well as to enable the creation of original resource description records. It includes a subset of MARC fields and uses language-based tags rather than numeric ones, in some cases regrouping elements from the MARC 21 bibliographic format. This schema is currently in draft status…
…the schema does not target round-tripability with MARC 21. In other words, an original MARC 21 record converted to MODS may not convert back to MARC 21 in its entirety without some loss of specificity in tagging or loss of data. In some cases if reconverted into MARC 21, the data may not be placed in exactly the same field that it started in because a MARC field may have been mapped to a more general one in MODS.

Compared to MARC, MODS is simplier and uses word tags (like name, titleInfo, and originInfo) instead of numeric tags (100, 245, 260).  There is not a 1 to 1 mapping between MARC and MODS, so conversion between the two might introduce some challenges.

Let’s look at the book example used in the analysis of the other standards:

Geary, Edward A. A History of Emery County. Salt Lake City: Utah State Historical Society, 1996.

The Library of Congress represents this book in MODS here.

The three key pieces of information (author, title, and publication) are represented in MODS as follows:

  <nonSort>A </nonSort>
  <title>history of Emery County</title>
<name type="personal">
  <namePart>Geary, Edward A.</namePart>
    <roleTerm type="text" authority="marcrelator">creator</roleTerm>
    <placeTerm type="text">Salt Lake City</placeTerm>
  <publisher>Utah State Historical Society</publisher>

Especially compared to MARC, this is much easier to understand. The title is shown between the titleInfo elements and splits the title into the non-sorting (/filing) portion and the rest of the title. The author’s name is contained in the name section identifying it as a personal name with the actual name contained in the namePart element.  The role
oleTerm is used to identify that the name is the creator of the source which by implication for a book is its author.  The originInfo section includes the publication information including publication place (placeplaceTerm), publisher, and publication date (dateIssued).

Something else I noticed about this compared to MARC is that extra punctuation (commas, periods, colons, and semicolons) are not included as part of the field values. This separates the formatting from the data which makes more sense to me.  I also like the ability of MODS to break out the name and describe the individual parts:

<name type="personal">
  <namePart type="given">Edward A.</namePart>
  <namePart type="family">Geary</namePart>

 This can give more flexibility when displaying the name in the Source List Entry (surname first), First Reference Note (given name first), and Subsequent Note (surname only).

When citing a book with multiple authors and those authors have a name prefix (ex: Dr.) and/or a name suffix (Jr., III, etc.) is becomes necessary to break out those name parts as well to aid in forming the citation.  This can be done in MODS as follows:

<name type="personal">
  <namePart type="termsOfAddress">Dr.</namePart>
  <namePart type="given">Benjamin Franklin</namePart>
  <namePart type="family">Gates</namePart>
  <namePart type="termsOfAddress">III</namePart>

Notice how both the name prefix and suffix are identified by the same namePart type attribute of “termsOfAddress”.  In MODS, the order of the elements does not imply any display order so for a computer program to know that the first termsOfAddress is a prefix and the second is a suffix it would have to parse the actual text value.  In my opinion, it would be more helpful if MODS identified them like this:

<name type="personal">
  <namePart type="prefix">Dr.</namePart>
  <namePart type="given">Benjamin Franklin</namePart>
  <namePart type="family">Gates</namePart>
  <namePart type="suffix">III</namePart>

There is more investigation of MODS still to be done to determine how it might represent additional citation details that isn’t usually found in the Source List Entry. Remember page number for book? Additional sample citations from Evidence Explained would need to be put to the test to see if MODS is a good fit. I do like the ability of XML to add additional namespaces to qualify elements and attributes. This could be a means of extending the MODS standard for any additonal details required.

1 Comment »

  1. Regarding the page number issue, MODS does have a mapping from MARC21 which includes the tag required for “analytic” cataloging: the 773 tag for Host Item Entry. So the MODS record would be a record for the part or piece being referred to and the 773 tag would be represented by the MODS “relateditem” tag which would provide details for the context in which the document is found.

    So the MODS record could be for a specific death certificate and the record would include a “relateditem” tag which would give details on the specific collection of death certificates from which it originated.

    Comment by Steven M. Law — 22 Jun 2009 @ 9:54 am

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