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: