Controlled vocabularies come in many shapes and forms: compiled as lists of keywords, structured hierarchically in thesauri and/or refined through the faceting of descriptors. There is a good reason to compile controlled vocabularies: to provide consistent access points. With control comes rules and ideas (and sometimes fierce debate) about how to structure and/or map a phenomenon, an activity or area knowledge.
The Powerhouse Museum Object Name Thesaurus (PMONT) – as described by its developers – has been generated as a means of providing consistent access points in the documentation of the Powerhouse Museum’s collection. The thesaurus documents material culture – made objects – and the terminology reflects the material culture developed in or imported into Australia. The strength of the thesaurus is its description of made objects from the past right up to the end of the twentieth century and beginning of the twenty first century.
Museums from around Australia have been using PMONT as a documentation tool – the thesaurus has been through two printings and is regularly downloaded. The familiarity with the thesaurus in the Australian museum sector and the use of the thesaurus around Australia to document artefact and archival collections was one of the primary reasons to move from having digitised it (making the thesaurus available as a downloadable document online) to computerising it (and making the thesaurus readily machine processable and usable as a terminology service). This shift in enabling access reflects increasing interest in providing online access to museum collection data. Collecting organisations providing resource discovery services are moving from providing online catalogues via websites to providing enhanced resource discovery, metadata aggregation services and linked data services.
As collection data is gathered up in the Museum Metadata Exchange the project team are also collating information about the other types of controlled vocabularies being used by the participating partners to document their cultural and historical collection material. As Sue Davidson says in her blog post about the Powerhouse Museum Object Name Thesaurus, the thesaurus reflects the collection strengths and breadth of the Powerhouse Museum’s collection.
There is a real challenge for the Registration and Curatorial teams at the Powerhouse Museum is to take in the feedback and work within an community of interest to seek input, possible extensions to strengthen and find the boundary to the PMONT. Particular interest will be paid to the areas of culture and history less well represented in Australian artefact and archive collections already identified: indigenous Australian and Torres Strait Islander, maritime, military, fine arts and audio-visual collection material.
There is no universal thesaurus of all things made – but there is real potential to be constructive about where other ontologies already developed about “made things” (and used by members of the Australian collecting community) prove useful to consider to use in addition (as another semantic layer) with Australian collection data or to augment the PMONT. There are several controlled vocabularies are in use in the museum collecting community that the project team are aware of: Getty Art and Architecture Thesaurus (AAT), the Australian Pictorial Thesaurus (APT), Schools Online Thesaurus (SCOT), and AIATSIS thesaurus (subject, name, language) to name but a few. There are controlled vocabularies used in related collecting and research areas, such as: Library of Congress Subject Headings (LCSH) and Australian Literature (AUSTLIT), and the numerous other <a href="http://www.loc.gov/standards/valuelist/" brary of Congress Subject Headings (LCSH) and Library of Congress controlled vocabularies and the many many independent vocabularies registered with the Library of Congress.
When there are similar vocabularies (terms in common) this is where the data modeling and methods behind the development of ontologies and standardisation (or ability to map to a common terminology or perhaps realise a grammar in common) becomes as important as the community of practice forming around shared vocabulary and community engagement. There is also a point where it is important to distinguish between different collections and domains and different reasons to apply terminology and what impact (and benefit) that distinction might have (for those that “manage” the data and collection and the “users” that the terminology is designed to serve – in the provision of intellectual access).
There are plenty of practical (and cultural) lessons around in the metadata world on how to work towards common schemas and controlled vocabularies and yards of philosophical literature on ontology and epistemology. The most obvious ontology in the form of a metadata schema in the collecting community is Dublin Core (DC). Dublin Core was developed and improved by many stakeholders as a high level metadata schema of 15 elements that has defined terms (See: DCMI Metadata Terms), has type vocabulary defined and the ability to “plugin” other encoded vocabularies. DC is simple and able to capture all kinds of information – DC is a broad church. There are many ways to extend schemas (like DC) to meet the particular needs of the material being described, to provide different types of metadata (to serve different functions) and the ability to provide multiple semantic “layers” in to improve resource discovery. Similarly controlled vocabularies can be extended where there is commonality required (and for general use) and/or where there is specificity required (and for particular use) and valuable.
The Museum Metadata Exchange is one step in the direction of aggregating museum collection data and providing a consistent semantic layer using the Powerhouse Museum Object Name Thesaurus. The feedback from project participants and observers will be critical to understanding how managing community input to the development of a controlled vocabulary might work best – and – looking for other semantic layers that are beneficial for the research, museum and wider collecting community to develop and utilise in common.