Project Status: Complete

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MARC Usage in WorldCat

This project will study utilization rates of MARC tags and subfields in WorldCat and produce tools and reports to that end. This provides an evidence base for testing assertions about the value of capturing various attributes by demonstrating whether the cataloging community has made the effort to populate specific tags, not just to define them in anticipation of use.


"Ground truthing" is the process whereby geographic remote sensing data is checked or enhanced by on-the-ground observation and measurement. We are attempting to perform a similar function for library cataloging. We have used the MARC standard for many decades, but how, exactly? Which elements and subfields have actually been utilized, and more importantly, how


This work seeks to use evidence of usage, as depicted in the largest aggregation of library data in the world—WorldCat—to inform decisions about where we go from here with the data that has been encoded using the MARC standard.


  • A set of web pages that report quarterly on the usage of MARC within WorldCat over 2013.
    • Additionally, tab-delimited text files that expose the actual data strings in selected subfields.
  • Software programs to produce the above.
  • Reports as requested for WorldCat Quality Control and/or the Library of Congress Bibliographic Framework Transition Initiative.