Dublin Core - information about who can access the resource or an indication of its security status


  • NSDL usage - information describing conditions or requirements for viewing and/or downloading NSDL material
  • Field usage - optional; absence of the field does not imply free access
  • Number of occurrences - repeat the field as necessary

Dublin Core: Access Rights vis-à-vis Rights

In Dublin Core, access rights is a refinement of the core element rights. Dublin Core provides the followingrights definition and further explanation of access rights:

  • Rights - information about rights held in and over a resource [Typically includes a rights management statement for a resource, or references a services providing such information. Rights information often encompasses intellectual property rights, copyright and various property rights].
  • Access rights may include information regarding access or restrictions based on privacy, security, or other regulations.


Rights information is typically a statement about intellectual property rights---that is, who claims ownership or control of a resource and its use and re-use. Intellectual property rights include the right to limit access to one's intellectual property. The access rights field conveys information about any conditions or regulations the rights owner may have imposed with regard to granting access to a resource.

Most resources and collections in NSDL can be accessed in their entirety at no charge. However, there are NSDL materials, that require registration, payment, or subscription for full access. NSDL recognizes the value of being able to describe a range of situations with regard to the conditions under which various users can access particular resources.

Controlled vocabulary terms and definitions

Terms are in bold italics. As necessary, definitions are provided.

  • Free access - the right to view and/or download material without financial, registration, or excessive advertising barriers
  • Free access with registration - the right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use
  • Available for purchase - the right to view, keep, and/or download material upon payment of a one-time fee (use for: membership access, buying of material )
  • Available by subscription - the right to view and/or download material, often for a set period of time, by way of a financial agreement between rights holders and authorized users (use for: course access by studentsindividual subscription, institutional subscription, subscription with free trial, pay-per-view, )
  • Limited free access - some material is available for viewing and/or downloading but most material tends to be accessible through other means [use for: free trial materiala site that includes an area of free accessible content]

Cataloging best practices

  • Use NSDL Access Rights terms to describe the availability of a resource, including the means of access (e.g. role, offline/online, membership, time) and the particular conditions (e.g. free, for purchase, or subscription) for viewing and/or downloading NSDL material.
  • Use the NSDL Access Rights terms to provide library users with a general (broad-brush) understanding of a resource's accessibility.
  • Complete Access Rights, only if such information can be determined. If it can not be, do no use the field.
  • Complete Access Rights by using the process below:
    1. Determine if the material will benefit from the use of the access rights field.
    2. Determine if an NSDL controlled vocabulary term is appropriate. If so, include an access rights field with the vocabulary term.
    3. If a concise statement regarding access rights is available via URL, include an access rights field that has the URL.
    4. If a vocabulary term is not appropriate or a URL is not available, include an access rights field that is a free-form description.
    5. If additional information needs to be provided, include an access rights field with this additional information.
  • If free access to material is limited to specific groups, such a members of a professional association or the affiliates of a university or other institution, use Available by subscription or Available for purchase, as appropriate.
  • Do not use NSDL Access Rights to describe how a resource may be used or re-used. Use the Rights or License fields instead to describe property rights associated with the use and re-use of a resource, including intellectual property rights.
  • If a resource requires users to log-in or register but otherwise offers total unfettered access, use Free access with registration.
  • The term Limited free access can be used in combination with Available by subscription or Available for purchase when there are a chunk of materials that are freely available.

Resource examples

Below is an italicized list of different kinds resources. The bullets under each resource represent the content that could be used as access rights information.

Rock sample kit

  • Accessible after placing an on order online
  • Available for purchase

Native American resource

  • Accessible during summer season


  • Limited free content
  • Available by subscription

Bulletin of Engineering Geology and the Environment

  • Available by subscription

Alice (an interactive 3D programming language)

  • Free access

teachers' domain (multimedia resources for the classroom and professional development)

  • Free access with registration


  • Available for purchase
  • Limited free content

  • Available for purchase
  • Limited free content

Elsevier science and technology books

  • Available for purchase

Professional society content

  • Available for purchase
  • Access is available depending on membership level

A Content Review System

  • Available by subscription
  • Access only available to administrators and editors

XML tips and examples

  • In addition to using URIs and describing access rights, select terms from the NSDL controlled vocabulary.
  • When using the NSDL vocabulary, indicate it in XML documents by using the 'nsdl_dc:NSDLAccess' refinement on the attribute xsi:type.
  • When using non-NSDL vocabulary terms, such as a URL to an access rights statement or page, do not use 'nsdl_dc:NSDLAccess' refinement in XML documents.

Using the controlled vocabulary

<dct:accessRights xsi:type="nsdl_dc:NSDLAccess">Available by subscription</dct:accessRights> (using an NSDL term) 

Not using controlled vocabulary

<dct:accessRights xsi:type="dct:URI"></dct:accessRights> (using URI)
<dct:accessRights>Access is only available from selected university domains. </dct:accessRights> (using own description) 
<dct:accessRights>Free access from ABC university </dct:accessRights> (using own terms)



This controlled vocabulary was approved October, 5, 2007.

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