MARC Usage in WorldCat
A summary of the use of MARC fields and subfields in the WorldCat database.
Ground Truthing the Use of MARC
"Ground truthing" is the process whereby geographic remote sensing data is checked or enhanced by on-the-ground observation and measurement. We are performing a similar function for library cataloging. Most libraries have used the MARC standard for many decades, but how? Which elements and subfields have actually been used, 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.
Visualizations
Visualizations of the data are available as well.
Available Data
Snapshots currently available include:
- 1 January 2018
- 1 January 2017
- 1 January 2016
- 1 January 2015
- 1 January 2014
- 1 January 2013
Archived quarterly reports from 2013 are also available.
Key
 | — The contents of one or more subfields is available for this tag |
 | — OCLC MARC documentation is available |
 | — OCLC MARC documentation is not available |
 | — Library of Congress MARC documentation is available |
 | — Library of Congress MARC documentation is not available |
 | — A bar chart of the data is available |
 | — Data is available for downloading |
MARC Usage in WorldCat is a project of OCLC Research.