Persistent  Identifiers 
 
              
Joanna McCloud 
 Johns Hopkins University 
MARAC Fall Meeting 2016 
In-house Systems   vs.   External Registries 
Just what is a Persistent Identifier (PID)? 
• Unique  &  adaptable 
 
• Actionable 
 
• Permanently assigned 
 
• Provides authentication 
 
 
 
 
 
 
In-house Systems   vs.  External Registries 
In-house 
• Less expensive 
• Complete control 
• Un-sharable inside & outside  
 
 
         External  Registries 
• Actionable & interoperable PIDs 
• Technical support 
• Data backup 
• Objects directed globally 
• Broken links 
• Data migration problems 
• Cost 
External Registries 
PURLs 
• Persistent Uniform Resource Locators 
 
DOIs 
• Digital Object Identifiers 
 
ARKs 
• Archival Resource Keys 
PURLs 
• Persistent Uniform Resource Locators 
 
• https://purl.oclc.org/docs/index.html 
 
• Example:  http://purl.fdlp.gov/GPO/gpo54200 
 
• United States Government Printing Office 
• National Library of Australia 
• Florida Center for Library Automation 
 
 
DOIs 
• Digital Object Identifiers 
 
• www.doi.org 
 
• Example:  doi: 10.12026/april2015 
 
• Library of Congress 
• American Psychological Association 
• MIT Press 
 
 
ARKs   &  EZID 
• Archival Resource Keys 
 
• https://wiki.ucop.edu/display/Curation/ARK 
 
• Example:  http://ark.cdlib.org/arkspec.pdf 
 
• EZID:  http://ezid.cdlib.org/ 
 
 
 
Link Testing - External Registries 
December 2015 
• PURLs  80% 
• DOIs  95% 
• ARKs  95% 
 
         October 2016 
• PURLs  85% 
• DOIs  95% 
• ARKs  95% 
PIDs  -  the Future of Digital Assets 
•  Institutions will continue to move away from in-house 
systems 
 
•  External registries will become the norm 
 
•  Greater global sharing of assets 
References 
Ducut, E., F. Liu & A. Ali.  (2008, June).  An update on Uniform Resource Locator (URL) decay in MEDLINE abstracts 
 and measures for its mitigation.  In BMC Medical Informatics and Decision Making, 8(23), 1-8.  doi: 10.1 
 186/1472-6947-8-23 
 
EZID.  Retrieved from http://ezid.cdlib.org/ 
 
Hilse, H.W., J. Kothe.  (2006).  Implementing Persistent Identifiers: Overview of concepts, guidelines, and recommendations.  
 Consortium of European Research Libraries, European Commission on Preservation and Access, 17-35.  
 Retrieved from  
http://webdoc.sub.gwdg.de/edoc/ah/2006/hilse_kothe/urn%3Anbn%3Ade%3Agbv%3A7-isbn-90-6984-508-3-8.pdf 
 
International DOI Foundation.  Retrieved from www.doi.org 
 
Online Computer Library Center.  Retrieved from https://purl.oclc.org/docs/index.html 
 
Tonkin, E.  (2008, July).  Persistent identifiers: Considering the options.  Retrieved from  
 http://www.ariadne.ac.uk/issue56/tonkin/ 
 
University of California Office of the President.  Retrieved from  https://wiki.ucop.edu/display/Curation/ARK 
Joanna McCloud 
jmcclou1@jhu.edu