Version 1.3 from 25/06/2018, authors: Monika Zarnitz / Yvonne Tunnat
The preservation policy of the ZBW – Leibniz Information Centre for Economics defines the institutional guidelines for digital preservation.
The ZBW jointly operates a digital preservation system with the two other subject-specific German National Libraries – the Leibniz Information Centre for Science and Technology University Library, Hannover and the ZB MED (German National Library of Medicine - Information Centre for Life Sciences, Cologne/Bonn).
The Preservation Policy of the three German National Libraries  defines the valid guidelines for digital preservation for all three libraries and the use of the jointly operated digital preservation system. The ZBW Preservation Policy defines the institutional guidelines of digital preservation relating to the collections of the ZBW and the interests of the ZBW users. The policy serves to make these guidelines available to the users of the ZBW and to the data producers.
The policy is reviewed at least once a year to verify that the collection guidelines or the digital preservation handlings are still up to date.
The ZBW acquires national and international literature corresponding to its collection guidelines (chapter 2.2), creates bibliographic and content descriptions, provides it for supraregional lending, and ensures the long-term availability of the contents.
2.1 Mandate, tasks, target groups
As the German National Library of Economics it is the task of the ZBW to acquire literature and subject-specific information from the field of economics, to index it, and to ensure its lasting availability to its target groups.
An ever increasing part of the collections, e. g. dissertations and working papers, is provided in digital form. The ZBW in its function as a subject-specific National Library is responsible for the long-term and sustainable availability of all digital content which it collects, licenses or produces by retrodigitisation of its collections, and which it archives on its own servers.
The economic research community at home and abroad counts among the ZBW user groups for digital preservation. Private enterprises and the interested public can also use the services and the holdings of the ZBW. The interests of these external groups must be taken into consideration by the digital preservation handling, although the digital preservation system of the ZBW itself is a so-called “dark archive”, which does not provide direct external access. Other target groups of the digital preservation are those ZBW colleagues who are responsible for those electronic services which are to be provided sustainably (e. g. the staff members responsible for the open access server EconStor).
2.2 Collection guidelines and selection
The collection emphases of the ZBW are part of the supraregional literature supply system of the German Research Foundation (DFG).
The ZBW acquires theoretical and empiric literature in economics and business studies. In addition, it also purchases all publications of neighbouring and ancillary sciences whose main focus is on economics.
The ZBW acquires economic literature from all over the world according to a country ranking. The decisive criterion for the selection of literature from economics or business administration is the academic significance of the publication. The ZBW acquires publications in the respective national languages, but in principle literature in German or English is preferred. All literature in economics and economic theory published in Germany is procured. This includes empirical and industry-specific publications, as well as those dealing with particular regions. The ZBW collects nearly all publications from the USA and the UK if they are relevant to economics. Publications from other countries are purchased selectively. Practical literature is collected only selectively.
One particular emphasis of the collection is on publications of international economic organisations. The ZBW holds all economically relevant publications of the European Union (EU) and its organs, as well as those of the United Nations (UN) and its organisations, the World Trade Organisation (WTO), the International Monetary Fund (IMF) and the World Bank.
Another emphasis of the ZBW collections is to acquire all publications of the world’s leading business schools and economic research institutes.
The ZBW procures all publications of its remit regardless of format, that is in print, as digital files or microform. The acquisition of so-called “grey” literature, that is material not published by publishing houses, is of particular importance .
The needs of the ZBW user groups determine the selection of contents for digital preservation.
The ZBW aims to ensure the readability of its digital collections for the long-term. Since file formats and interpretation software can become obsolete very quickly, and the information contained in the digital data can only be made readable again with a high effort, the ZBW engages in digital preservation to minimise the risk of digital data becoming obsolete.
Usually the material hosted by the ZBW on its own servers is archived when no further changes are expected concerning the object itself and its metadata. If a change occurs after having been archived, however, the material is updated within the archive. The original data is always preserved additionally and will not be removed.
The team Digital Preservation is an inherent part of the ZBW. The ZBW prefers automated processes and workflows to spare its personal resources and to be able to master the growing number of digital objects. This is the reason why the workflows are scalable to a multiple of the current digital holdings.
The ZBW also aims to follow the commonly used best practices, and to have its diligence, reliability and transparency regarding the digital preservation of its digital holdings certified, e. g. with the Data Seal of Approval and the nestor Seal (based on the DIN-Norm 31644 .
It is the mission and the aspiration of the ZBW team Digital Preservation to be up to date with technical innovations, to watch them, to be informed about the newest developments and best practices of other institutions engaged in digital preservation, and to adjust the ZBW digital strategy accordingly. If it is possible and useful, national and international conferences are attended to stay in touch with the many developments in the area of digital preservation. The ZBW is also active in the German-speaking competence network nestor  and in the internationally active Open Preservation Foundation .
All previously created descriptive metadata are handed over to the digital archive with the digital object. If there is an entry in the union catalogue GVK , the digital objects are enriched additionally with the metadata from the union catalogue. Additionally, technical metadata are extracted automatically which are useful to ensure long-term readability (see “Metadata in the ZBW Digital Archive“ ).
Usually, the permission to archive is granted by the data producer. If the data producer has not granted the explicit right to preserve the content, digital preservation takes place on the basis of the statutory exceptions.
3.4. Preservation level
Pure bitstream preservation only preserves the bitstream. Bitstrean Preservation makes no provision for editing objects.
As a principle, the ZBW aims to not only preserve the bitstream of its acquired and created digital material, but to preserve and ensure the readability and usability over time. This may include the migration to other file formats which are more suitable for long-term availability (3.7).
For some objects, however, this is not possible. This is true e. g. for password-protected data which prevents any editing of the data. The law does not allow the circumvention of this kind of protection. If it is impossible or denied to attain a password-free version of the contents, only the original bitstream of the corresponding objects will be preserved.
The integrity of the archived data is checked via checksums after each reading access. Since the data is saved redundantly, the corrupted data which might contain bit error can immediately be replaced by an intact version.
3.6 Preservation of authenticity
The original data which was ingested into the archive is preserved in principle. The additional presentations (derivatives) which serve the preservation of long-term readability are archived in addition and do not replace the original (Risk management and preservation planning in the ZBW Digital Archive ).
The contents in the archive are preserved completely, which means that all files and metadata which belong to one intellectual entity are always preserved as a whole.
3.8 Preservation of legibility
If the ZBW Digital Preservation team can influence the file format in which the objects are acquired from the data producers or – in the case of digitization – in which file format the data is created, the following guidelines apply (see “Preferred file formats in the ZBW Digital Archive” ):
- standardized (e. g. via an ISO-norm)
- not depending on only one or few display tools
- (preferably world-wide) distribution and widely used
- open format or format is made open retroactively
In line with the risk management and preservation planning, previously archived material is migrated into preferred file formats where possible. Preservation planning includes checking that file formats present in the archive are current, and quality checks of the archived material in terms of compliance to the file format specifications. Detailed information about risk management and preservation planning can be found in the corresponding workflow documentation .
Every object in the digital archive has at least one persistent identifier in its metadata which is also part of the metadata in the original representation platform. In addition, each object receives an identifier within the digital archive.
All descriptive and technical metadata are actively searchable, so that the material is retrievable in various ways within the archive. If it is useful, the objects are bundled into logical sets or collections.
3.10 Observance of confidentiality
The digital archive offers a detailed access rights management with various configuration options. This guarantees at all times that no unauthorized persons can access the material and all embargo periods can be met. Although the digital archive is currently only used as a “dark archive”, all copyright-protected contents are identified as such, in case that the archive is converted into a “light archive” with external access before the embargo period expires.
All configurations and workflows used in the digital archive are documented and are regularly updated and published for all staff members in digital preservation within the three National Libraries.
In addition, tutorials are created which document the workflows, facilitate the use of the workflows for new staff members, and mitigate the risk of faulty work. The workflows are also published for staff members who are responsible for the material on the access platforms like EconStor.
All workflows are regularly optimized, and developed further, and the documentation updated correspondingly.
3.12 Access and use
The Digital Archive does not provide any external access and is used as a dark archive only. Only the ZBW Digital Preservation Team can access the archived material.
Access to the digital data takes place on the corresponding representation platforms (EconStor in the case of the ZBW). If there are access limitations, these are currently only managed by these representations platforms.
The digital archive is used by the three subject-specific German National Libraries. The digital archive consists of all parts which are described in the OAIS-model:
- data management
- archival storage: The storage is managed by the TIB in Hanover
(Preservation Policy of the three German National Libraries).
- preservation planning
- administration: e. g. user management
- access: Only staff members can access the data
Digital Preservation is a permanent task of the ZBW and is ensured sustainably and in the long term. Securing digital data is part of the overall collection care. Responsibility for the creation and the regular update of this preservation policy lies with the ZBW Digital Preservation Team.
 Preservation Policy of the three German National Libraries
 Fachinformationsdienste für die Wissenschaft, S. 5
 Collection guidelines of the ZBW
 The Data Seal of Approval was awarded in the autumn of 2015.
The nestor Seal was awarded in October 2017.
 Open Preservation Foundation
 GVK Gemeinsamer Verbundkatalog
 Risik management and preservation planning in the ZBW Digital Archive
 Preferred file formats in the ZBW Digital Archive
 Metadata in the ZBW Digital Archive