Tier A-C requirements
- Adina Ciocoiu
- Henning Scholz
Good quality metadata allows you to make your collections more discoverable and reusable in the Europeana website and beyond. It also allows Europeana to market your material to a greater extent, include it in our thematic collections and exhibitions, incorporate it into projects and applications, and facilitate its use in research and education.
To help you improve the quality of your metadata, we have outlined three criteria: language, enabling elements and contextual classes. Each criterion can be assessed for its score on a scale of three tiers (A, B, C), while the overall metadata tier level can only be reached if all three criteria meet the conditions for that level. For example, if one criterion reaches level C and another criterion reaches level A, then the overall tier would be A.
The metadata tier requirements are valid for all edm:type values.
Language
Language tags are used to specify the language for EDM metadata elements with text string values (as opposed to references), represented using the xml:lang attribute with the appropriate language code. The language code should be taken from a controlled list, for instance the 632-2 list, the IANA language tag registry, or the Languages Name Authority List (NAL).
Adding language tags (xml:lang) to the metadata elements that have text string values specifies the language of that value and allows its reuse in a multilingual environment like the Europeana website. This is especially true if the metadata is available in several languages - providing for instance translations in other languages. A language tag helps to display metadata in the language that best suits the user (given that the user has the option to select a preferred language) and improves searching and browsing overall.
Each tier requires a set percentage of language tags in the metadata. The percentage for the language criterion is calculated based on the proportion of the relevant properties from edm:ProvidedCHO that have at least one language qualified value.
The tier calculation considers dereferenced resources and Contextual Classes attached to the ProvidedCHO.
Dereferencing, in Europeana context, refers to the action of extracting information from Linked Open Data vocabularies provided in EDM fields.
Please note that language qualified values in Contextual Classes do count if they have been either submitted by the provider or generated by Europeana from a dereferenceable link (URI) to contextual entity found in the source data, when these are attached to the ProvidedCHO, Aggregation and WebResources.
Enabling elements
In addition to the mandatory EDM metadata elements, the Data Quality Committee (DQC) has defined a list of enabling elements which can support particular user scenarios. Including one or more of these EDM metadata elements in your metadata allows for greater information retrieval and service improvement in the Europeana website and third-party platforms that use Europeana data, such as in the research sector (e.g. CLARIN).
For more information on the enabling metadata elements for each scenario see the Discovery and User Scenarios. The list of enabling metadata elements that is considered in the context of the EPF is provided below.
Contextual classes
Linking and adding information to your metadata helps to contextualise the provided cultural heritage objects and makes them easier to retrieve. EDM accommodates four (optional) contextual classes (edm:Agent, edm:Place, edm:TimeSpan, skos:Concept) which can be used to capture distinct entities that are related to the cultural heritage objects.
For the contextual classes, we recommend the use of references (links) to multilingual and Linked Open Data (LOD) vocabularies, like Getty AAT, Wikidata or Geonames. Doing this will result in enriching your metadata by adding, for instance, the translation of terms making the item more findable for people speaking different languages. Contextual classes will be considered relevant for the tier calculation, only when all minimum required metadata elements have been included in the data.
Note that if (links to) contextual classes are not provided in the source metadata, some may still be generated as a result of Europeana’s own semantic enrichment.
Enrichment, in Europeana context, refers to the process of adding additional information based on the terms (string values) used in certain metadata fields. The enrichment process matches those values with the same values found in LOD vocabularies.
These Europeana references to contextual metadata do not count for the tier classification, however.
Overview Metadata tier requirements
Tier | Language | Enabling elements | Contextual classes |
A | At least 25% of the metadata elements from edm:ProvidedCHO class that are relevant have at least one language qualified value | At least one metadata element from one of the ‘Discovery scenario’ groups present in the edm:ProvidedCHO class | None |
B | At least 50% of the metadata elements from edm:ProvidedCHO class that are relevant have at least one language qualified value | At least three distinct metadata elements taken from two distinct ‘Discovery scenario’ groups present in the edm:ProvidedCHO class | At least one contextual class with all minimum required elements, OR link to LOD vocabulary |
C | At least 75% of the metadata elements from edm:ProvidedCHO class that are relevant have at least one language qualified value | At least four distinct metadata elements taken from two distinct ‘Discovery scenario’ groups present in the edm:ProvidedCHO class | At least two contextual classes with all minimum required elements, OR links to LOD vocabularies |
For detailed requirements per Metadata Tier see below: