Developments on Common Core State Standards Identifier and XML Representation

As 45 states, the District of Columbia, and two territories move from widespread adoption of the Common Core State Standards to implementation, there is a need to appropriately identify and link assets using a shared system of identifiers and a common XML representation. There have been several prior efforts at this. The Council of Chief State School Officers (CCSSO) and National Governors Association Center for Best Practices (NGA Center), working closely with the standards authors, aim to put forward a viable approach for publishing identifiers and XML designation to represent the standards, consistent with their adopted format, as outlined below.

  • Canonical identifiers for individual standards - Rather than force a decision between three competing options, CCSSO and the NGA Center have decided that the following three options have distinctive values and should be published together simultaneously.

    Unique identifiers are needed for humans and technology to refer to individual standards in a consistent manner. Three sets of canonical identifiers, as detailed below and now readily available on www.corestandards.org in draft format, will maintain fidelity to the published and adopted documents, while acknowledging the wide variety of use cases, users and systems needing to reference the standards

    • Dot notation including those from the published and adopted standards documents, e.g. Math.6.EE.1, useful for conversation and displayed with the text of a standard. Published identifiers will necessarily follow a different nomenclature in mathematics than in English Language Arts (ELA) and literacy because the standards documents themselves follow a different system in each discipline. These differences have been adopted by states.
    • De-referenceable URIs at the corestandards.org domain, e.g. https://thecorestandards.org/2010/math/content/6/EE/1 or https://thecorestandards.org/2010/math/practice/MP7. Matching the published identifiers, these deferenceable URIs allow individuals and technology systems to validate the content of a standard by viewing the web page at the identifier’s URL. CCSSO and the NGA Center strongly recommend that www.corestandards.org remain the address of record for referring to standards.
    • Globally unique identifiers, e.g. A7D3275BC52147618D6CFEE43FB1A47E. These allow, when needed, to refer to standards in both disciplines in a common format without removing the differences in the published identifiers. CCSSO and the NGA Center recommend strongly that the CCSSO unique identifiers be used for this component of the work.


    All individual standards and lettered sub-items; all anchor standards in ELA; and all practice standards in math, as well as cluster headings in math, have received identifiers. CCSSO and the NGA Center have not provided numbers for reading headings such as “craft and structure” or “key ideas”, since these headings were intentionally left un-numbered and since they do not strictly define different domains in reading. In math, however, cluster headings have an important design function in organizing the subject matter and in adding important meaning to the individual content standards; math cluster headings are also proving crucial in implementation efforts. Therefore math cluster headings have been given identifiers (such as A, B, C, for example). By this means, the identifiers preserve links between standards and clusters, which is necessary to ensure that applications using the system can preserve the meanings that arise from considering the cluster headings and the individual content standards in conjunction with one another. De-referenceable URIs will also include data relative to material revisions, e.g. https://thecorestandards.org/2010/math/content/6/EE/1r1.
  • XML and metadata - The XML representation of the standards and the embedded metadata within the HTML pages at www.corestandards.org (to be available in the coming months) will represent the intent and language of the standards and go no further. Hierarchies and relationships that exist in the adopted documents will be reflected in the data files, but other data points not specifically codified will not. The corestandards.org XML file will follow the Common Education Data Standards (CEDS) schema, also used by Schools Interoperability Framework Association (SIF). To incorporate the three identifiers, minor changes will need to be made to the CEDS schema, and those will be submitted to the CEDS Stakeholder Group for consideration in CEDS version 3.0. We leave it up to individuals and organizations to decide whether to keep or replace their current data files.
  • Granularity - For both assessment and instruction, there is a need to attach assets to the standards at a finer grain level than the published documents. Be that as it may, there is no canonical way to subdivide an individual standard. To the contrary, it is a major act of authorship to break individual standards into parts. Such acts of authorship came to a close when the standards document was adopted by states.

    There is also no single way to divide an individual standard that is best for all purposes. Efforts to break down the standards must proceed based on particular purposes; standardizing the breakdown once and for all would not only be a new act of authorship; it would be counterproductive so therefore CCSSO and the NGA Center do not intend to officially release the standards at a finer granularity.

    CCSSO and the NGA Center do, however, encourage collaboration among organizations to complete any break downs of the standards necessary to support implementation efforts and stand ready to participate in this process where helpful. But a standardized view of how the standards should be subdivided is neither viable nor desirable.

    Next Steps:

    • A draft data file containing the three sets of canonical identifiers is now available.
    • The NGA Center and CCSSO will recode www.corestandards.org to match the new URI structure and XML and metadata vocabularies in the coming months. When the recoding is done, a final notice of its completion will be sent.
    • The NGA Center and CCSSO will submit the metadata vocabulary to Creative Commons and www.schema.org.
    • The standards authors have agreed to collaborate with CCSSO and the NGA Center on a webinar for states and information on this will be forthcoming.