Getting Persistent Identifiers Implemented By ‘Cutting In The
Middle-Man’
R. van Veenendaal
National Archives of the Netherlands
The Hague
The Netherlands
remco.van.veenendaal@nationaalarchief.nl

M. RasNational Coalition for Digital Preservation
The Hague
The Netherlands
marcel.ras@ncdd.nl

ABSTRACTThe Persistent Identifier (PID) project of the Dutch Digital
Heritage Network (DHN) promotes sustainable access in thecultural heritage domain by stimulating the use of PIDs as
references to (digital) cultural heritage objects. PIDs are longlasting references to objects and offer a solution for link rot,which often results in 404 or Not Found error messages.
Cultural heritage organisations, regardless of size, are often
hesitant to implement PIDs in their systems. They lack knowledgeof PIDs, are unaware of the capabilities and benefits of PIDs, andfear possible complex and costly implementation processes aswell as the maintenance costs for sustained services.
To address these issues, the DHN PID project focussed on:Raising awareness of (the importance of) PIDs in cultural
heritage organisations



Increasing knowledge regarding the use of PIDs withincultural heritageSupporting the technical implementation of PIDs in cultural
heritage collection management systems

At the time of writing, four vendors have implemented PIDs in thecollection management systems (CMS) they provide1, and a dozen
cultural heritage institutions are taking part in this pilot
implementation phase. More importantly however, is that throughthese CMS vendors, PIDs have become more available andaffordable as a sustainable long term access solution for hundredsof institutional digital collections and their users. To ensure thatthe information, training and education the project provided about
PIDs can be disseminated and used as widely as possible, theproject created (best practice) documentation in Dutch andEnglish, along with a unique PID Guide for learning about PIDs
and taking the first steps towards selecting a suitable PID solution,
along with a PID implementation Roadmap. This was an effort toencourage the adoption and use of PIDs in the cultural heritage

1

These vendors, and the collection management systems they implemented PIDs in,are: Picturae (Memorix), DeventIT (Atlantis), De Ree (MAIS-MDWS), Cit (TheMuseum System).

M.C. Dangerfield
Rotterdam City Archives
Rotterdam
The Netherlands
mc.dangerfield@rotterdam.nl

domain, by utilising their existing collection management systemvendors.
The concept of ‘cutting in the middle-man’ – cooperating withcollection management system vendors and supporting theimplementation of PIDs in their products – has proven extremely
successful, and the outcomes of this project may help cultural
heritage initiatives in other countries to get PIDs implemented intheir organisations too.

1

INTRODUCTION

Link rot, links resulting in a 404 or Not Found HTTP error
message, is a nuisance to internet users and a threat to thesustainable availability of online cultural heritage and scientificinformation. Especially when links have been harvested and are(re)used in cultural heritage portals and aggregators like
Europeana, broken links can have a significant impact.
Museums, libraries, archives and scientific organisations in the
Netherlands are joining forces to fight link rot by implementing
Persistent Identifiers (PIDs) in their (collection management)
systems. PIDs are unique and permanent links to (digital) objects.
The Digital Heritage Network (DHN) established a PID
project to raise awareness of PIDs, increase knowledge regarding
the use of PIDs, and support PID implementation projects.

2

DIGITAL HERITAGE NETWORKThe DHN is a partnership focused on developing a network ofnational faculties and services for improving the visibility,
usability, and sustainability of digital heritage in the Netherlands.
The network was established as an initiative by the Dutch
Ministry of Education, Culture and Science and is undertaken by
several key institutions and experts relating to the area of digital
heritage [1].
The DHN has developed a three-pronged strategy covering
Visible, Usable and Sustainable aspects of Digital Heritage. For
each of these aspects a work package has been establishedoutlining projects necessary to achieve their core goals. The
Sustainable work package is coordinated by the Netherlands
Coalition for Digital Preservation (Nationale Coalitie Digitale

Duurzaamheid, NCDD). The PID project2 is one of the projects in
the Sustainable work package, and is managed by the National
Archives of the Netherlands. The first phase of this DHN program
ran from September 2015 to June 2017.

3

PERSISTENT IDENTIFIERS

A Persistent Identifier is a unique and permanent link to a(digital) object, e.g. scan, audio file, metadata record, web page,or book. In the context of the internet, PIDs are posed as asolution to the problem of link rot: where web pages become
inaccessible when a link or site address is changed. This isespecially common when websites link to each other. When site
addresses change (because the contents have been moved to a newpage, for instance, or because the organisation maintaining the site
has changed its domain name), the links no longer point to a valid
address, resulting in a 404 or Not Found HTTP status code. With
the rise of aggregators like Europeana3, and the increasing
availability of (linked) open data, link rot has become a serious
threat to the sustainable findability of digital cultural heritage. The
metadata of digital objects are harvested on a large scale andreused on various websites, and if the original address is thenchanged, thousands or even millions of links can suddenly break.

4 THE PERSISTENT IDENTIFIER PROJECTThe Persistent Identifier project promotes sustainable accesswithin the cultural heritage domain. Cultural heritageorganisations, regardless of size, are often hesitant to implement
PIDs. They lack knowledge of what PIDs are, don’t know about
the capabilities and benefits of PIDs, and fear a possible complex
and costly implementation process as well as the maintenancecosts for a sustained service.
To address these issues, the project worked on:Raising awareness of (the importance of) PIDs in cultural
heritage organisations

Increasing knowledge regarding the use of PIDs withincultural heritageSupporting the technical implementation of PIDs in cultural
heritage collection management
The project ran from September 2015 to June 2017, and willcontinue in a follow-up project in the second phase of the DHN
program.

4.1

Raising AwarenessTo raise awareness, the PID project first created an inventoryof cultural heritage organisations currently using PIDs, and thosethat did not. Organisations using PIDs were asked to share their(best) practices with us. Organisations not yet using PIDs wereinvited to workshops and presentations, for which training andeducation material was created. A PID Roadmap was also written,
2explaining the most important steps in a PID implementation
project: preparation, implementation and publication, and thesubsequent management of PIDs.
The PID project made extended efforts to educate a wider
audience about the importance of PIDs, by publishing articles in
the magazines Archievenblad and Informatieprofessional [2], also
resulting in an online PID dossier4, and regular communication
through the DHN’s social media channels. Three videos wererecorded and published in Dutch and English: ‘What are
Persistent Identifiers’, ‘Choosing the most suitable Persistent
Identifier’, and ‘Implementing Persistent Identifiers’5.

4.2

Increasing Knowledge

Once a cultural heritage organisation is aware of theimportance of PIDs, they often notice that they need to learn more
about PIDs and the various PID options, and eventually select one(or more) to implement. There are multiple PID options, including
Archival Resource Keys (ARKs6), Digital Object Identifiers(DOIs7), the Handle System8, OpenURL9, Persistent Uniform
Resource Locators (PURLs10) or Uniform Resource Names(URNs11). Each system has its own particular properties,
communities, strengths and weaknesses. But which one is best
suited to a particular organisation’s needs? Choosing a PID
solution is an important decision with long-term implications. To
help cultural heritage organisations learn and think about
important PID aspects, and to guide them through their first steps
towards selecting a PID solution, the project developed a PID
Guide. The Guide was developed in collaboration with PID
experts from Delft University of Technology (for DataCite DOI),SURFsara (the Handle System) and the National Library of theNetherlands (for the URN:NBN namespace). DataCite DOI, theHandle System and URN:NBN are the three most used PID
solutions in the Netherlands.

4.3

The PID Guide

The PID Guide reuses the idea of Voting Advice
Applications12 and guides participants through 25 statements
about PIDs. The participant is presented with 5 options to choose
from per statement. These options reflect a 5-point Likert scale[3]. The outcome of this guide points towards a preference for one

4

See http://www.informatieprofessional.nl/bijdragen/2016/06/dossier-oplossingen-voor-/, visited 2017-03-29.
5

See the NCDD YouTube channel

https://www.youtube.com/channel/UCvHDarEQeREkRVLdzJSbKWw, visited 201703-29.
6

See https://confluence.ucop.edu/display/Curation/ARK, visited 2017-03-29.

7

See https://www.doi.org/, visited 2017-03-29.

8

See http://www.handle.net/, visited 2017-03-29.

9

See http://www.oclc.org/research/activities/openurl.html, visited 2017-03-29.

10

See https://archive.org/services/purl/, visited 2017-03-29.

persistent-identifiers/, visited 2017-03-29.

11

See https://en.wikipedia.org/wiki/Uniform_Resource_Name, visited 2017-03-29.

312

See https://en.wikipedia.org/wiki/Voting_advice_application, visited 2017-03-29.

See http://www.ncdd.nl/en/ncdd-projects/digital-heritage-network/projectSee http://www.europeana.eu/, visited 2017-03-29.

or more PID solutions. More importantly, the participant haslearned and thought about 25 important PID issues in the process.
The preference(s) calculated by the Guide should not be seen
as a definitive choice for a particular PID solution. Other factors
not represented in the guide may affect the final decision. An
organisation may also be part of a community that has a strong
preference for a particular PID solution. Where the Guide does
not rule out any PID solution, an organisation could haveshowstopper criteria for selecting a PID solution, such as cost,level of support or formal standardisation.
PID solutions are rarely restricted to national borders, andwhile the PID Guide was written with Dutch requirements in
mind, the 25 statements and technical setup are transferable
internationally. We therefore welcomed reviews of the PID Guide
by the International DOI Foundation13 and nestor14. Their
feedback helped improve the PID Guide before publication.
Additionally, the PID Tutorial held at iPres 2016 [4], resulted ininterest from other countries (to translate the PID Guide) andcommunities to create a more comprehensive PID resource(including, e.g., more PID solutions). The PID Guide has a CC0
license15 and is freely reusable16: www.ncdd.nl/en/pid-wijzer.
At the time of writing, 91 participants have used the PID
Guide. Participants are asked to provide information about their
type of organisation, job title and collection management system.
This gives the project valuable information regarding the types oforganisations using the PID Guide, and their (resulting)preferences. After filtering out incomplete entries, the data from69 participants, including 23 international participants, was used
to calculate preferences for PID solutions in the organisation types
archive, library, museum, science and other.

The bar chart from figure 1 is based on the average preferences
resulting from the PID Guide. For each participant, the resulting
preference scores for all (3) PID solutions are used as input. The
chart shows a preference for handles in museums (based on 18
participants), a preference for URN:NBN in libraries (20participants), and a preference for DataCite DOI in research
institutions (10 participants). Archives (16 participants) have aless clear preference for a particular PID solution. In the Other
category, URN:NBN is preferred. This is however based on alimited set of 5 participants, mostly from commercialorganisations. Given the limited number of participants for thissurvey and the fact that no immediate follow-up research has yet
been undertaken, figure 1 is a first sketch of the kind of
information that can be gathered from the PID Guide. In time, we
hope to receive more data from PID Guide participants, andanalyse the PID Guide’s database in greater detail. The results
could help focus future PID advocacy and implementation efforts.

4.4

Cost

The cost of (implementing) PIDs is an important issue. Whilesome PID solutions are free, i.e. have no annual fee, the combined
cost of implementation, maintenance and use is never zero. In thepast, the cost of PID solutions has been a major inhibiting factor
in PID implementation in cultural heritage organisations. For
example during the Continuous Access to Cultural Heritage(CATCH, 2004-2014) and CATCHPLUS (2009-2012) projects,
important steps were taken towards implementing PIDs in cultural
heritage organisations, but the cost of using PIDs remained an
obstacle for widespread uptake17. The timing of this PID project
was more fortunate. The establishment of EPIDC18, thefoundation of DONA19 and changes in SURFsara’s organisational
policies led to affordable Handle System based PID services
becoming available for cultural heritage organisations. With
URN:NBNs provided for free by the National Library of theNetherlands, and clients of Delft University of Technology’s
DataCite DOI service required only to pay an annual fee of €750
per prefix, the basic annual cost for using the major PID solutionsin the Netherlands are all below €1,000 and within financial reachof most cultural heritage organisations regardless of size20.
One important cost issue remained: the cost of implementing
PIDs within collection management systems. This is where thecutting in the middle-man strategy of the PID project came intoplay. Instead of requiring individual cultural heritage organisation

Figure 1: preliminary PID Guide preferences for organisation types.
17

See for CATCHPLUS http://www.catchplus.nl/en/pids/index.html, and, for

information about the cost obstacle13

See https://www.doi.org/, visited 2017-03-29.

https://www.edata.nl/0903_010615/pdf/Het_bemiddelen_tussen_vraag_en_aanbod_z

14

See

it_in_mijn_genen.pdf (in Dutch), both visited 2017-03-29.

http://www.langzeitarchivierung.de/Subsites/nestor/EN/Home/home_node.html,

18

See http://www.pidconsortium.eu/, visited 2017-03-29.

visited 2017-03-29.

19

See https://www.dona.net/, visited 2017-03-29.

15

See https://creativecommons.org/publicdomain/zero/1.0/, visited 2017-03-29.

20

Free DOI services, like Zenodo, figshare and Dataverse were not taken into

16

We are discussing the transfer of the stewardship of the PID Guide to the Openconsideration. Their modus operandi include uploading objects, and most cultural

Preservation Foundation, thus further increasing its international visibility andheritage organisations have published or want to publish and manage theirsustainability.

collections in their collection management systems.

to finance a tailor-made PID implementation project, the PID
project offered to pay for the initial implementation costs to thevendors, under the proviso that a generic and reusable solution
was developed. In theory, the implemented PID solution should
become available to all users of that (collection management)
system.

4.5

Cutting in the middle-man

Via the projects’ various communication channels, workshops
and presentations, word spread that support for PID
implementation was available. This led to talks with vendors ofcollection management systems working with Dutch cultural
heritage institutions. As a result, at the time of writing, 4 of the 5
key software vendors have started implementing PIDs in theirsystems, together with a variety of pilot institutions:
Picturae21, together with the Noord-Hollands Archief,Archief Eemland, Regionaal archief Zutphen, Groninger
archieven and Regionaal archief Tilburg, have made handles
available in Memorix software,
DeventIT22, together with the Centraal Bureau voor deStatistiek, Regionaal Archief Nijmegen and Gemeentearchief
Ede, are implementing handles in Atlantis,

De Ree Archiefsystemen23, together with Regionaal Archief
Rivierenland, are implementing handles in MAIS-MDWS,
Cit24, distributor of The Museum System, are implementing
handles with the Wereldculturen group, which counts theTropenmuseum, the Afrika Museum and Museum
Volkenkunde as user institutions.
These vendors and their clients discussed possibilities and their
institutional preferences, and in all cases, a preference for the
Handle System based PID service from SURFsara was chosen.
One of the benefits to this solution seems to be that PID
registration and maintenance can be handled automatically, via an
APID. The PID project has also started discussion with the Dutch
representatives of the Axiell Group25 regarding theimplementation of PIDs in the Adlib software.
Each vendor has a specific business model and annual feeschedule for the provision of PIDs in their systems. Most see PIDs
as a service that should be available in modern collection
management systems, and keep their fees relatively close to theminimum tariff set out by SURFsara’s PID service. The aim of the
project was to make the provision of PIDs advantageous for allparties, which has been achieved by this cutting in of the middleman.

21

See https://picturae.com/, visited 2017-03-29.

22

See https://www.deventit.nl/, visited 2017-03-29.

23

See https://www.de-ree.nl/, visited 2017-03-29.

24

See http://www.go2cit.nl/en/, visited 2017-03-29.

25

See http://alm.axiell.com/, visited 2017-03-29.

4.6 Best Practices
The collection management system vendors that implement
PIDs and the cultural heritage organisations that use them, wereasked to share their experiences from the implementation projects.
Their shared experiences will help encourage other organisationsin the future. Their experiences have been gathered in a bestpractice document. As the template for these documents has thesame headings as the PID implementation Roadmap, a consistent
feedback loop was created: organisations starting a PID
implementation project can use the PID Roadmap, and their bestpractice documentation helps fill a library of PID implementation
project experiences, which helps improve the Roadmap.

5

CONCLUSION

The DHN PID project set out to raise awareness of PIDs,
increase knowledge regarding the use of PIDs, and support PID
implementation projects. The project’s results show that the
project’s approach was successful.
The PID information, training and education material used inworkshops and presentations contributed to raising awareness,
together with PID Roadmap and best practice documents. The
unique PID Guide is still actively used by organisations forlearning about PIDs and taking the first steps towards selecting asuitable PID solution. SURFsara’s Handle System-based PID
service has become available to cultural heritage organisations at
an affordable price, ensuring that all major PID solutions in the
Netherlands are now available for less than €1,000 per year. Most
importantly, by cutting in the middle-man, PIDs have been
implemented in (4) leading collection management systems in the
Netherlands, and are available to all their (inter)nationalcustomers.
Although the DHN is a national program, the results of the
PID project can have an international impact. DataCite DOI,URN:NBN and the Handle System are available internationally.
Other countries or communities can also choose to reuse thematerials, PID Guide and the concept of cutting in the middleman.

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[3] R. Likert. 1932. A technique for the Measurement of
Attitudes. Archives of Psychology, 140, 1-55.
[4] J. Clark, R. van Veenendaal, M. Lunghi and J. Hakala 2016.
Persistent Identifiers for Cultural Heritage. In Proceeding of the
13th International Conference on Digital Preservation (iPres
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