Permanence of the Scholarly Record:
Persistent Identification and Digital Preservation – A Roadmap
A. Dappert

A. Farquhar

The British Library
96 Euston Road, London, NW1 2DB
UKangela.dappert@bl.uk
orcid.org/ 0000-0003-2614-6676

The British Library
96 Euston Road, London, NW1 2DB
UK
adam.farquhar@bl.uk
orcid.org/0000-0001-5331-6592

ABSTRACTThis paper proposes steps towards a roadmap for improving the
integration of two communities that deal with persistence andlong-term stewardship of digital content. They are Persistent
Identifiers (PIDs) and Digital Preservation. Both disciplines havemade significant progress and practical contributions. Yet theirapproaches are not fully linked and there is considerable potential
to integrate their solution space and to improve either of them bylearning from the other. It addresses three core issues:
1.

How does the long-term digital object life-cycle affect PIDs,
the entities they identify, and the metadata that describes
them?

2.

How can PIDs help long-term preservation?

3.

How can long-term preservation help to shape PID bestpractice and ensure long-term access to the scholarly record?

We also sketch out initial results of our ongoing work along thisroadmap.

KEYWORDS
Persistent identifiers, digital preservation, scholarly record,roadmap, distributed collaboration

1 INTRODUCTION
The Persistent Identifier and Digital Preservation communities
both address core issues related to persistence and long-term
stewardship of digital content. They have made significant
progress and practical contributions over the past two decades. In
spite of addressing shared challenges, the opportunities for each tobenefit from the other’s progress remain largely unrealized. This
paper addresses three core questions to provide a roadmap toimprove sharing of results:
1. How does the long-term digital object life-cycle affect PIDs,
the entities they identify, and the metadata that describesthem?
2. How can PIDs help long-term preservation?
3. How can long-term preservation help to shape PID bestpractice and ensure long-term access to the scholarly record?
While the work described can be applied to any digital material
that is worth preserving, we emphasize the scholarly record. It ischaracterized by complex sets of contributors and long chains of

information creation and exchange. These necessitate globallyunique persistent identifiers more than many other digitalmaterials.

1.1 Space, Time and Intent
Persistent identifiers (PIDs) play an important role in the scholarly
infrastructure. They enable both people and computational agentsto reliably identify and link to entities such as articles [e.g.
provided by Crossref 1 ] or data [e.g. provided by DataCite 2 ].
Furthermore, they can be used to identify researchers [e.g.
provided by ORCID 3 ] or rights-holders living or dead [e.g.
provided by ISNI4]. PIDs are becoming an essential component in
the workflows of funders, researchers, research organizations,data centers, publishers, libraries, and others. As of 2017, tens of
millions of PIDs have been assigned to these core scholarly
entities through global PID service providers and their partners.
Trusted and reliable identifiers associate a resource with acharacter string. The following PID criteria hold (inspired by [1]).
A PID is a name, rather than an address.
PIDs are globally unique.
PIDs are persistent.5
PIDs are selective at the right level of granularity.
PIDs are interlinkable.
PIDs are interoperable with other identifiers.
PIDs are designed to last beyond the lifetime of any systemor (most) organizations.
•
PIDs are globally resolvable as a URI with support for thefull range of HTTP including content negotiation.
•
PIDs are managed through a sustained committedorganization and governance process.
•
PIDs come with metadata that describes the resource’s most
relevant properties.
PID services mint PIDs on request and provide services such as
registration, metadata management, fragment identification,
content negotiation, search and discovery, and governance.
Content owners manage the content and ensure that content

•
•
•
•
•
•
•

1

https://www.crossref.org/
https://www.datacite.org/
https://orcid.org/
4
http://www.isni.org/
5This refers to the PID itself. It does not imply that the content must be persistent at
all times. For example, the content may be streamed or be versioned.
2
3

location information is kept up-to-date with the PID service.
Because both the PID service and the content owners holdmetadata that describes the identified resources, PIDs can beindexed and searched. PID service providers, such as DataCite,
establish a contractual governance commitment with content
owners to ensure long-term stewardship and accessibility of theidentified resource.
Leading motivations for PID use lie in the stewardship of thescholarly record. PIDs “improve the ease of locating resources;
are actionable on the Web; enable metadata update andcorrections without losing the resource’s identity; can integrate
legacy naming systems; promote linking and interoperability
between services; and reduce confusion among versions of a
resource. Widespread uptake of PID e-Infrastructures canaccelerate the adoption of Open Science by building trust throughseamless discovery of scientific artefacts; clear attribution tocontributors; traceable provenance; unambiguous citation inscholarly discourse; supporting reproducibility; and enabling
improved metadata quality through linking connected metadata
sources.” [2].
PIDs can be applied to publications, data, other research outputs,
researchers or other personas, organizations, legal entities,
funding instruments, projects or patents, and more. They can also
be used to distinguish aspects of an entity such as separate
versions, multiple formats, levels of granularity; or of an object,such as its intellectual definition (e.g. a FRBR work or
expression), or its rendition consisting of a bitstream, a single file,or a composite set of files.
PIDs and the relationships between them create a connected
network of information about the global scholarly record. This is agraph in which the metadata of one PID relates to that of another

PID. PIDs can and are being used in the workflows of funders,
researchers, research organizations, data centers, publishers,
libraries, and others. Most of the discussion has been around their“contemporary” functions in the processing, use and reuse ofresources, such as in data center or publisher workflows.
It is important to note that the scholarly record and this graph andthe resources within it are used across three dimensions:Space: semantic linking of PID-identified resources creates
the open eScience landscape in which we can globallyconnect and analyze data and associated metadata. This isemphasized in linked open data environments.
•
Intent: Resources can be reused and re-purposed in waysthat were unanticipated during their creation.
•
Time: The life-cycle of research and the scholarly recordspans centuries. It reaches from the conception of researchideas to reuse of results decades or centuries after theircreation.
There has been much work towards creating the connectedscholarly record and enabling validation and reuse of research
outputs. In contrast, relatively little effort has gone towards
ensuring long-term access to the scholarly record. It is this last
dimension, “time”, for which this paper outlines a roadmap for
future work.
Use cases across time include reserved PIDs for preliminary
research outputs; transfer of responsibility for an entity from acreator or publisher to a memory institution; use of PIDs andcontent resolution after format migrations that are necessitatedthrough obsolescence; handling deleted or lost data; PID creation
for data that are created within memory institutions, when large
data collections are mined resulting in derivative data sets; andprovision of long-term stewardship for identified content.

•

Figure 1: PIDrelated
information
flow among
stakeholders

THE SCHOLARLY RECORD LIFE-CYCLE

How does the digital object life-cycle affect PIDs, the entities they
identify, and the metadata that describes them? To investigate thiswe need to look at the following issues:
1. What role should PID stakeholders play in order to ensure
long-term preservation?
2. How can one manage the distributed long-term
responsibility?
3. How can PIDs support entities that evolve over time?
4. How can we preserve the PID graph as it grows over time as
more links are established through incremental
improvements, use and reuse?

2.1

Role of stakeholders in ensuring long-termpreservation of PID-related information

Stakeholders

While PIDs are sometimes created for local use only, they are
inherently about global reuse and establishing the connectedscholarly record. Therefore, PID-related information is passedalong from one organization to another across the life-cycle. They
include:PID services6
Funders
Research organizations
Researchers (as producers, consumers and reviewers)
Publishers
Data centers
Institutional information managers
Citation managers7
Indexing services8
Public content repositories9
Private content repositories10
Libraries and archives

Information
Objects

The Information Objects that are exchanged between thesestakeholders are of three different types, with differing relations to
the longevity of the scholarly record.
PIDs
Metadata
Content

6… that mint and manage PIDs and their associated metadata, such as DataCite,
Handle, CrossRef
7
Such as Mendeley, Zotero
8Such as Google Scholar, CrossRef, JISC KB+, SHERPA RoMEO, Directory ofOpen Access Journals (DOAJ), EBSCOHost.
9
Such as Zenodo, Github
10
Such as the Internet Archive

Business Actions

2

The stakeholders perform different Business Actions on the
Information Objects over the life-cycle.
Funding
Research management
Institutional information management
Research
Impact assessment
Reviewing
Publishingetc.
Each business action consist of a sequence of basic actions that
affect the Information Objects in the following ways.
CreateUpdateEnrichReplace
DeleteTransform formats
Disambiguate
etc.
Basic Actions

We investigate the role that memory institutions and digitalpreservation practitioners play in the use and preservation of
PIDs, their accompanying metadata, and the content theydescribe. Much of this is done by raising research questions
whose answers will help improve both PID use and digitalpreservation practice.

Figure 1 shows an information network graph for PID-related
information flow among the various business actions. Each node
represents a class of business actions (e.g. PID service provisionor provision of institutional information repository services); alink represents a flow of information objects (PIDs, metadata, orcontent). The nodes shown correspond to currently active actions;the links correspond to flows that are fairly well established as of2017. Several actions may be performed by the same actor; e.g. anational library may provide PID services, run a web archive andperform long-term content management. A link implies that there
is an information flow between some of the relevant actions
covering some of the information objects. Reviewing thisrepresentation highlights links that are desirable for long-termpreservation of the scholarly record, but may not be sufficient, oreven exist, at the moment.
Where links are not well established, it is not possible for an actor
to obtain information reliably or without substantial effort. Often
links exist, but they do not pass along all of the valuable metadatathat is associated with a PID. For example, in order for a library toacquire the information it needs about a dataset, it may benecessary to retrieve one subset from a data center, and anotherfrom a PID service provider.
A question is whether the information network has the links thatare desirable in practice. For example, currently, there are nowell-established links that inform Libraries and Archives about
metadata updates in external PID Services, or that enables
researchers to export PID-related metadata from Libraries andArchives into Citation Managers, or that pass rights metadatafrom PID Services to Researchers or from Data Centers to
Libraries and Archives.
Even in the case that there are good links in the information
network, it is not always clear who is responsible for assuring thelong-term usability of an Information Object. To answer this, weneed to know how each organization type can best contribute tothe assurance for long-term maintenance of the scholarly record;
determine where in the life cycle it is easiest or most effective tocreate PIDs; determine where PIDs should be enriched withmetadata; and when to perform other essential Actions.
2.1.1 Rules. As with all information creation, some rules-ofthumb apply. The closer information is collected to the source of
creation, the easier it is to obtain and the more authority it holds.
The longer-lived the custodial organization is, the more trust
exists in its continued ability to support the information. The
sooner in the life-cycle good housekeeping applies (such as
assigning PIDs), the easier it is to avoid violations of theinformation on the way. The later in the life-cycle a stakeholder ispositioned, the better is their ability to provide guidance on
uniform formats and vocabularies and to grant comprehensive
access. The later in the life-cycle a stakeholder is positioned, themore contradictory assertions may have accumulated about an
identified entity and the more doubt there is on the provenance of
metadata.
One step in the roadmap is to investigate these rules and which of
the stakeholders should best be responsible for each Action /Information Object pair. For example, what metadata should becreated by PID service providers to support long-termpreservation? What content or metadata format transformations
should data centers perform to support long-term preservation?
2.1.2 Longevity of organizations. Different stakeholders havedifferent ideas of what long-term means. For example, timelimited organizations such as projects may produce web content
with a life-span of months. Data centers have a considerably
longer outlook, perhaps a decade or two. Institutional repositories
are often private in nature and have no inherent incentive toprovide links for capturing the overall scholarly record. Whilethey may be long-term in nature, they do not have a long-term
mandate, such as national cultural heritage institutions. Open
Access repositories, such as Zenodo, assign PIDs and can function
as an intermediary for content that has no other organizational
PID support, but may not have the long-term mandate of anational cultural institution. Similarly, privately heldorganizations dedicated to long-term access, such as the Internet
Archive, may be more vulnerable than public institutions such as
national libraries and archives that are backed by a national
commitment.
National memory institutions have a fundamental long-term
mandate and can offer a safety net for valuable cultural andscientific assets. This applies to the metadata and content
associated with PIDs; it also applies to content that is nototherwise eligible for PIDs because it does not have a long-termhome. What new roles should these organizations play in thelong-term preservation of the scholarly record? Who takes
responsibility for creating PIDs and for creating metadata that is
associated with the PID?
Considering the information network and the varying long-term
commitment of the stakeholders in the scholarly record, there are
two crucial questions to address:•

How should the handover of Information Objects between
stakeholders be governed and managed?

•

Who takes responsibility for minting PIDs?

2.1.3 Handover. There are many pragmatic questions that must
be addressed to ensure that the handover of Information Objects
between stakeholders is effective. These include:
•

•

•

11

Where should business-as-usual handover of any information
related to the scholarly record be initiated? Should handovers
be defined and governed in a systematic manner? How canbusiness models of different organization types define a
hand-off best practice, as we are already familiar with from,for example, the hand-over between records management
systems to archives? How is responsibility to be transferredtechnically?
What should happen when preservation trigger events occur?
As a proactive example, online digital research repository
Figshare 11 has joined the Digital Preservation Network(DPN) 12 . Their announcement states that “Research data
made public on Figshare will be deposited into DPN, a darkarchive that preserves scholarship for future generations.
Figshare users can guarantee that long-term access to theirscholarly resources will be protected in the event of any typeof change in administrative or physical institutional
environments.” Similarly, some journal publishers subscribe
to the CLOCKSS dark archiving system to protect against
the case that they may no longer be able to make their
outputs available. A more reactive example of a sustainable
governance migration is the handover of the PURL 13 PID
service management from OCLC14 to the Internet Archive15,
which has a declared long-term business model 16 . In theevent of organizational failure, there should be mechanisms
in place for both the identifiers and the identified entities
with a governance structure and a method to offer resolution
and access services.
Who should be responsible for aggregating the distributed
scholarly record? PID services collect metadata on identified
and related entities. This may give the impression that theyguarantee the long-term availability of the scholarly record.
But PID services have limited scope; their mandate only
extends to the persistence of the identifiers, discovery
metadata, and resolution services. For example ORCID’s17
main goal is to provide PIDs for researchers. ORCID alsocollects information about these researchers’ scholarly output
such as alternative person identifiers, histories, funding,patents, and associated works. But it is not clear that it is
ORCID’s responsibility to guarantee this metadata for the
long-term. Where is the right scope for each of these PID
services?

https://figshare.com/
http://duraspace.org/articles/2769
http://www.archive.org/services/purl
14
http://www.oclc.org/
15
https://archive.org/
16
https://www.oclc.org/en-UK/news/releases/2016/201623dublin.html
17https://orcid.org/
12
13

Conversely, how do we ensure that the PID graph is fully
connected where possible so that there are no unintended
islands of information?
•
What is the role and responsibility of a national library inpreservation of globally distributed metadata that is
associated with various PIDs across multiple independent
providers?
•
Metadata associated with content is often deleted upon
handover between stakeholders. This may be for very goodreasons. For example, when an image is shared on the web,one may wish to remove identifying information to comply
with data protection regulations. If there are multiple copies
of some content that is identified by a PID, there may bedifferent metadata associated with each copy; how can adigital object consumer identify which copy holds themetadata they need or are entitled to?
2.1.4 PID minting responsibility. Organizations can only mint
PIDs if they make a long-term commitment to enable access to theidentified content. But there is valuable scholarly content, forexample in the form of blogs, that has no dedicated long-term
champion.
Webarchives in public and private content repositories and innational libraries and archives can provide persistence for some ofthese digital assets that do not have owners who can commit totheir long-term accessibility. An interesting proposal by Zierau etal [3, 4] bases these assets’ persistent identification on thepersistent identification of the web archive itself. A PWID
consisting of an identifier for the web archive, the harvest datetime, the harvested URL, and the context specification permits
persistent global identification of any harvested web content withthe guarantee of permanence provided by the webarchive, rather
than the content originator.

•

2.2

Managing distributed long-term
responsibility

No single organization today holds even a copy of the fullscholarly record including PIDs, associated metadata, and theidentified content, much less holds an authoritative copy. While
concentration of information can simplify large-scale use, it may
increase the risk of large-scale loss. Distribution and redundancy
offer a form of resilience and improved availability. Given thisdecentralization of stewardship, how can one manage the
distributed long-term responsibility? How can one avoid
discontinuities in modeling and interfaces, to ensureinteroperability at the edges of organizations’ scope?
The Scholix 18 framework offers a conceptual model, an
information model, information standards and encoding
guidelines, and options for exchange protocols toward solving
interoperability issues. It is “a high level interoperability
framework for exchanging information about the links between
scholarly literature and data”. But there is also a need fortechnical, governance, and coordination solutions, in particular for18

http://www.scholix.org/

providing long-term availability of the scientific record without
requiring a central uniform repository.
If this information is distributed over the global web and exposed
through shared protocols, it is available for dynamic harvesting
for as long as the information is available on the web. But weknow that web sources appear and disappear at alarming rates.
There is a natural role for long-term stewards, such as national
memory institutions, to harvest, preserve, and potentially provide
access to the scholarly record.
For long-term stewards of information, questions arise as to thebest models for managing PIDs that have been minted by multiple
sources that possibly duplicate or overlap; or for content that has
been combined from multiple sources.
As research advances, the scholarly record keeps growing. Overtime, more links are established through incremental
improvements, use and reuse. How can comprehensive harvestingof the scholarly record be assured for this? How can completenessbe assured? How can one deal with contradictory sources ofevidence?

2.3

How can PIDs best be used to support
entities that evolve over time?

The scholarly life-cycle involves entities that are evolving overtime. There may be changes to metadata or content. When, forexample, datasets and software identified by the PID service
change or related versions are created, one must track how eachversion relates to earlier ones. Each version may be identified by a
new PID and linked through meaningful relationship types.
Whether or not changes establish a substantially different object
that deserves the assignment of a new PID depends on the usecase that is supported by it, and on the policies that underline theuse case. For example, changing the spelling on an author’s namemay be considered a minor correction that does not necessitate theassignment of a new PID to a book. There is no use case thatwould handle the corrected object differently. Even so, one cankeep a cumulative trace of any corrections. Adding an author to abook may necessitate the creation of a newly identified object,because it may be necessary to reflect the fact that different
copyright assumptions were made before and after the correction.
That is to say, there is a use case that results in different actions
on the two identified objects. Therefore, one should distinguishthe corrected object from the earlier one through a new PID and
one should record the relationship between them, as well as theevent and the policy that necessitated the creation of the new PID.
As a consequence, it is not the PID service that determines at whatlevel of granularity PIDs should be assigned. PIDs support theclients’ use cases. The PID services have to flexibly accommodate
different client policies and use cases.
But this also implies that PID service providers have little control
over the resulting granularity of the research objects that are
identified. It is then the PID minting clients that can negotiate
among each other to establish guidelines on policies that bothsupport the implemented use cases and support interoperability
and information exchange between different institutions.

These dynamics don’t only apply to defining what use cases
trigger versioning, but also to controlled vocabularies or the
granularity at which PIDs are assigned to digital objects. For
example, different even types necessitate the creation of a new
PID for a derivative dataset. To support long-term managementof evolving research data one would want to record the dataset’s
provenance by recording the relevant events. These events types
are typically defined by a controlled vocabulary, such as“software patch applied”, “time-filter applied”. The PID service
can define suggested controlled vocabularies, but the client must
be able to use their own personalized vocabulary to meet theirindividual use cases.
One of the key R&D questions is, therefore, what functionality
needs to be provided by PID services to enable their clients tocapture the necessary versioning information about evolving
entities. Initial discussions can be found in [5].
Memory institutions are practiced in dealing with these questionsin the context of their digital repositories. Digital preservation
metadata work, as discussed in Section 4 has provided
recommendations for how to handle these situations that now canbe applied to new contexts, such as PID services.

3

MEMORY INSTITUTIONS - PIDs HELPLONG-TERM PRESERVATION

Using PIDs can improve processes for institutions that need tosatisfy a long-term mandate.

3.1

Authority control

Wikipedia [6] states that in “library science, authority control is aprocess that organizes bibliographic information, for example inlibrary catalogs by using a single, distinct spelling of a name(heading) or a numeric identifier for each topic. … These one-ofa-kind headings or identifiers are applied consistently throughout
catalogs which make use of the respective authority file, and areapplied for other methods of organizing data such as linkages andcross references.” Authority control supports information
management and is shifting toward PID-based rather than stringbased solutions. This is a significant change in the information
management practices in memory institutions that helps to avoid
shortfalls of string-based authority practices, such as spelling
errors. For example, using an ISNI for current or historic rights
holders or an ORCID for self-registered researchers supports
precise unambiguous identification in citation, information
linkage, or even authentication.
The roadmap needs to identify:•••

What PID functionality is needed to transition from stringbased authority or local identifiers to globally unique PIDs?
What adjustments are needed in memory institutions’workflows to transition to PID-based authority control?
What adjustments are needed in PID services and governanceto meet the quality, scalability, affordability, and otherrequirements of memory institutions?

3.2

Infrastructure for preservation of the digitalscholarly record

Digital preservation is a form of long-term information
management. Institutional repositories can provide local storage
and archiving for scholarly outputs and they are equipped to
manage metadata and some content. Realistically, the ability topreserve the wide array of research object types, such as non-SQL
databases, is limited and needs further work. Furthermore,
repositories are not equipped to provide content resolution
services to replace failed PID services. The practice in PID
services can inform improvements in digital preservation services
in this regard. And, as mentioned earlier, repositories have
limitations in managing PID related metadata when they are notthe organization on record and known to the service that minted
the PID.
If memory institutions harvest content from the web, PIDs can bevery helpful, but still have implementation inconsistencies thatprevent effective automated harvesting. We need to improve
managing long-term data and artifacts that include PIDs so thatthey can be used to better streamline digital preservation efforts.
For an example, see Van de Sompel, Rosenthal, Nelson’s [7]discussion on eJournal preservation.

3.3

PID use in digital preservation repositories

In digital preservation, identification of digital content is essential.
In the contemporary scholarly process, PIDs are used forvalidation and reuse of research results. Long-term reuse ofmaterial that is held by memory institutions is even morechallenging, since the material is created and consumed by third
parties. Reuse happens over much longer periods of time. As aresult assumptions about the environment and context required areless likely to hold. This makes PID use even more important. But
by far not all content in digital long-term repositories is identified
through PIDs. Most digital repositories deal with a variety ofidentifiers, most of which lack one or more of the PID criteria
outlined above. It is essential to understand how long-term
repositories can enhance existing local or transient identifierswithin their scope to support the PID criteria.
PREMIS states [8] that “for a given identifier to be usable, it isnecessary to know the identifier scheme and the namespace inwhich it is unique. If a particular repository uses only one type ofidentifier, the repository would not need to record the scheme inassociation with each object. The repository would, however,need to know this information and to be able to supply it when
exchanging metadata with other repositories.” This requirement
only ensures that an entity is identifiable within one repository. To
support a global information network, it would require very
precise knowledge about when a scheme was applied, how thescheme changed over time, how the versions relate, and so on. As
Information Objects flow through the information network,
chances are that a long-term repository would not be able tocollect the essential information in external schemes to establish
identifyability. The question to address is how PID use can
support this information flow.

Another aspect of long-term information management is a needfor heightened resilience. The longer-lived content is, the more
likely it is that parts of the information object may inadvertently
be corrupted. For example, we have anecdotally witnessed that thelinks between PIDs and their associated metadata have beenbroken through software programming errors so that PIDs could
no longer be linked to the content they identified. In order tomitigate this sort of risk it is advisable to not solely rely on PIDs,
but to judgmentally enrich them with redundant metadata thatwould permit a semantic match of entities between distributed
long-term systems if the PIDs themselves get corrupted. The
questions that arise are, what metadata is best suited to serve thispurpose, and how best to ensure synchronization of redundant
metadata in multiple places.

3.4

Other archival tasks that can benefit from
PID useMany more entities are managed in memory institutions’information governance. Ideally there would not only be PID
services for research outputs and agents (persons andorganizations), but also for funders, grants, laws, patents, software
packages, events, etc. Every PID service requires a governancestructure, a metadata scheme, and support for information creationand exchange. These are currently missing for many entity types.
Memory institutions are now also creating new and derived data
sets related to their digital collections through text and data
mining, analysis, crowd sourcing, and citizen science. Stable waysof identifying these data sets, their provenance and theircontributors need to be implemented.

4

PID SERVICES - LONG-TERM
PRESERVATION HELPS TO SHAPE PID
PRACTICE

The digital preservation community has developed an array ofpractices and techniques for long-term information management.
How can this help to shape PID best practice and ensure longterm access to the scholarly record? Where are gaps in PID
services’ current practice that can be informed by memory
institutions’ practice?
A key answer is the metadata that is associated with PIDs and theentities that are identified by them. PREMIS [8] is the de facto
metadata standard for long-term access to digital content. It
recommends the information about digital content that is very
likely needed for long-term use and preservation. Its goal is toensure the availability, identifiability, integrity, viability,
renderability, understandability and authenticity of digital content.
PREMIS articulates data modeling and metadata principles thatshould be adopted early to remove vulnerabilities for digitalcontent and to ensure its long-term usability. But PREMIS does
not just address digital preservation. A file can become unreadable
because its format has become obsolete over years or because
there was a power failure during file transfer today – bothsituations require similar consideration. Therefore, the approachtaken in PREMIS can be helpful for near-term management ofdigital content.

Figure 1 illustrated how metadata that is associated with thescholarly record is passed through a network of stakeholders’actions until it ends up in memory institutions for long-term
content management. The stakeholders involved in the scholarly
information network can benefit from those PREMIS principles.
For example, PID services, such as CrossRef or DataCite, arejustified in specializing on content types, such as scientificarticles, monographs, or data sets. As their portfolios grow toaccommodate newly supported types, their data models need to beextended. The first-principles approach taken in PREMIS helps toensure that data models are both extensible and interoperable.
Since PREMIS is expressed as framework and principles it can be
implemented in any implementation environment.
Future work should articulate those recommended PREMIS
features, perform a gap analysis to understand to what degree they
are currently not supported with scholarly stakeholders, what
implications this has for the long-term access to the scholarly
record, and how these short-comings could be overcome.
An initial set of example recommendations of how stakeholders inthe scholarly information network can adopt good practice fromPREMIS is discussed in the following.
PREMIS distinguishes Objects, Actors (including, people,
organizations and computing components), Rights statements andEvents, which are sufficient to support modeling most semantic
relationships required. Objects can be described on four separate,
declared levels:
the intellectual description that helps search and find theobject;•representations, which are sets of files that together create
one rendition or execution of a digital object;•component files of each representation;•and individual bitstreams.
Efforts that model digital objects without distinguishing theselevels often end up confusing issues that should be separated. For
example, some PID solutions conflate resolution to a landing pagethat holds descriptive information (similar to the intellectual
entity) with resolution to the content itself (which could be a
representation, file, or bitstream). This lack of clarity hinders
automatic crawls, machine-harvesting and machine-interpretationof parts of the scholarly record. Van de Somple et al. [9, 10]
analyze this situation for web use of PIDs. Adopting the PREMIS
model would resolve this challenge. Different users may need toresolve to different levels. For example, a crawl bot may just wantto find representations and files; a search indexer may just be
interested in intellectual entities and descriptive metadata;someone running an impact analysis may just want to identify the
researchers and, from there, link to their research outputs. Becauseof these varying use cases and goals the underlying
conceptualizations need to clearly identify the types of entities ofinterest. This results in access mechanisms that support these use
cases flexibly. PREMIS entities are sufficient to support modelingmost semantic relationships required to capture these distinctions.
Technical metadata, as specified for PREMIS objects, should becreated as early as possible in the information network (e.g.,•including information about file types, checksums, creating
software, or computing platform requirements).
The PREMIS model covers derived, dependent or structurally
related objects and provides a transparent way of relating themwith each other. Each relationship can document the nature of therelationship, and the events and agents that were involved increating it. As we have seen in Section 2.3, this ability isimportant to support use cases for many of the actors that rely on
PID services.
PREMIS provides two powerful tools for identifying anddescribing partial and dynamic datasets. The first one is the ability
to describe and identify bitstreams (mentioned above). If datafragments can be described as sets of bitstreams, they can bedirectly identified and described.
Sometimes they are, however, better described by the event thatcreated a dynamically derived subset (e.g., for data sets that arederived from a base data set by applying a filter). This can beaddressed by events associated with relationships. The derived
dataset can be identified by annotating its relationship to theoriginal data set with an event that captures the selection criteria
or selection algorithm. The derived data set is identified, but does
not actually need to be instantiated; it can be computed on
demand from the original data set. In this way PREMIS modelingcan be used to support the implementation of the RDA
recommendations for Data Citation of Evolving Data [11] within
its basic inherent data model and without the need for creating any
extended functionality for special cases.
Relationships also let you relate data sets that are related througha structural hierarchical inclusion relationship on various levels of
granularity. PREMIS objects can be used to describe software andhardware or other parts of the computation stack, which areessential components in the scholarly record that are currently notadequately covered by PID services. Adopting PREMIS
compatible conceptualizations would make it easier to provide
PID support to these object types and to support interoperability
among scholarly stakeholders.
Another example is the maintenance of provenance information in
the scholarly record. Provenance may contain events from any
point in the object life cycle. For example, they might record due
diligence activities, or events that transform an object or its
metadata. It is important to record these events to determine thedegree of authenticity of the object over time.
PREMIS events also encourage linking to event-related agents,
ranging from data creators to researchers, curators, to publishers,
but also organizations or software agents. This form of modelingdoes not simply identify the role of an agent with respect to an
object, as is currently frequently done, but it specifies in which
event this role was taken. This allows for a much more precise
and time-linked recording of the agents’ roles.
CrossRef and DataCite are starting to collect and distributeinformation about events related to PIDs. For example, when an
article cites a dataset or when a new version of a dataset isreleased. Currently, this is not based on a generalizable event
model, and it does not extend to provenance events. The
responsibility for this sort of information may mainly lie with
their clients, but PID service providers should consider collecting

it as additional assurance. Again, adopting the PREMIS modelingstyle for events (or agents or rights) can improve interoperability
across the information network and simplify informationexchange.
These examples illustrate some of the PREMIS features whose
adoption could improve the information exchange in the scholarly
information network. Future work may investigate how theseprinciples can best be translated to individual implementation
environments.

5

CONCLUSIONSWe set out to investigate how Persistent Identifier services can beextended to long-term information management. When starting toaddress this, we realized that the number of unsolved issues was
substantial and should not be addressed ad hoc. A more
systematic analysis of the research and development space was
required to combine lessons from the two domains. Consequently,
this paper sets out key questions and challenges for a roadmap toimprove the alignment between Persistent Identifier and Digital
Preservation approaches. Due to the real advances that have been
made in each community, this alignment may enable a moredeliberate design rather than stepping through ad-hoc
improvements. Enhanced aligned services involved in creating
and maintaining the scholarly record would support a more
complete information flow. The resulting data models would
explicitly support long-term preservation of PID resolution
services, metadata that captures information about the scholarly
record, as well as access to the actual research objects.

ACKNOWLEDGEMENT
This work has received funding from the European Union’s
Horizon 2020 research and innovation programme under grant
agreement No 654039”. We would like to thank our reviewers
Herbert Van de Sompel, Ignasi Labastida, and Barbara Sierman
for suggesting work in this area.

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