The RDF legal dictionary is technically innovative in a number of ways. The main one is that it uses RDF (Resource Description Framework) to describe XML Schema documents. This is a new way of using RDF, which is a structured data format particularly suited to creating typed links between documents. More usually RDF has been used to describe HTML web pages, for example for creating metadata for describing a web page using the Dublin Core vocabulary (http://www.dublincore.org/). Here we use it to describe the content not just of individual XML pages but W3C XML Schema pages, themselves written in XML. An XML Schema expresses constraints on any XML document that conforms to that schema. But it also effectively summarises the possible content of all conforming XML documents, so that instead of creating data describing each individual XML document, we can simply describe the schema, and then state that documents conforming to the schema containing element x can also be described as being of type y. If successful, this technique represents a major increase in efficiency in the creation of links between documents, and the method will be applicable to any XML schema-based application. It can be used, as in this case, for creating what might be called a common vocabulary for describing a particular subject such as Law, with minimum re-cataloguing effort and no change to the original documents to create cross-mappings between different XML schemas.
XML is becoming extremely important to businesses in the EU. It provides the flexibility of producing machine-readable structured data for any application. This flexibility has a tendency to lead towards interoperability, and commonly a business, organisation or government will begin with an in-house XML vocabulary for its documents, and only later need to share documents with another organisation with its own format. Using RDF to map between XML Schemas and a common vocabulary provides an extensible and scalable means of mapping between schemas without either organisation having to change the data held in databases or documents, because the method is really one of annotating schemas using RDF. The method is generic to XML, and so can be used in other arenas.
The traditional classification of legal terms is a hierarchy. The broadest term stands at the top, refined by narrower terms. Each (narrow) term has no more than one broader term as its „parent“. Hierarchical classification is, after a flat list, the easiest way to classify terms. For a long time people have been aware that hierarchical classification is a rather inadequate way of describing legal reality. The reason that hierarchical classification remains the most practised way of classifying probably lies in the means of storage. Any piece of information should be stored just in one place. If one stores it in more than one place, the possibility of inconsistencies is created. Unless stored in a computer system, this requirement usually can be satisfied only in a flat list or hierarchical structure. Of course the strict hierarchical structures in such traditional systems are often softened by card indexes, thesauri and other cross linking methods. But the basis is and remains a hierarchical structure.
Legal databases have, so far, in practice not brought any significant other method of storing and retrieving, apart from full text search. Full text search offers relief in some cases, in many cases it is a rather inaccurate and inefficient way to find one’s way in an information surplus.
Legal ontologies promise development in this field, certainly where they apply RDF based ontology languages like DAML+OIL. RDF breaks through hierarchy by allowing multiple inheritance. A (narrower) term can have more than one broader term as parents. A legal ontology contains a structured view of the legal system, which view potentially comes closer to legal reality than traditional structured views.
What does the RDF Dictionary add to these developments? The RDF Dictionary is not a legal ontology, at least not in the traditionel sense. It does in itself not try to describe the legal system. What it does, is link structures to one another. It facilitates the interoperability, the communication, between data structures. Such a structure is in most cases an XML Schema, describing the structure of a particular kind of legal document, like judgement or contract. The legal RDF Dictionary not only links these structures, it also offers a user the possibility to compare various structures and use the structure which best suits his needs at that moment for the particular task he is performing. A structure once made is in principle static. As things change over time a structure may in parts loose its usefulness. The RDF Dictionary makes sure a user can always choose to use the latest structure. He may even mix parts of structures, as RDF offers the capability of mixing namespaces. Namespaces in this context are nothing more than one particular XML Schema or a legal ontology.
As it is often problematic to translate legal terms litterally from one language to another language (each term being embedded in its own jurisdiction and legal culture) the RDF Dictionary uses legal "Archetypes" to map key legal concepts across language and jurisdiction borders. An example for judgement/Urteil/vonnis can be found in a very first draft for an RDF Dictionary (http://rdf.lexml.de). Judgement is described by its aspects, each aspect being a legal Archetype, like: "written", "enforceable", "subject to appeal", "rendered by a public body", "preceded by proceeding between two or more parties".
The innovations covering a wide range of possibilities, the proposal has chosen one application to show the advantages of these innovations. A web interface which makes use of XML Schemas to enable a user to access a foreign website, retrieve and interpret its information in a better way than he could have than without the web interface. Furthermore he is offered information related to a retrieved document. „Foreign“ in this context means a legal system which he did not study and a language which is not his mother tongue (and may even to a large extent be incomprehensible to him).
An improvement in information retrieval means a gain of time and quality, in particular in the profession of a lawyer where information is the main material to build the product of a lawyer: documents. The re-usability of retrieved XML-data in the documents to be written increases these advantages. XML with the RDF Dictionary concept can improve the communication between lawyers, thereby again increasing efficiency and quality. Also the communication between citizens and their governments may be increased through better retrieval of legal information.