XML Schemas for use in local elections have been published as part of the UK e-Government Interoperability Framework (e-GIF). These XML Schemas have undergone public consultation and have been agreed by the Office of the e-Envoy. The Schemas represent a UK adaptation of the EML International Schema developed by the OASIS Election and Voter Services Technical Committee. The distribution contains some 33 XML Schema (.xsd) files and an overview document EML: Customisation for UK Local Elections. The specification includes an introduction on (optional) validation of EML-UK document using Schematron schemas.

From the Background statement for 'EML: Customisation for UK Local Elections':

As an international specification, EML is generic in nature, and so needs to be tailored for specific election scenarios. Some aspects of the language are indicated in EML as required for all election scenarios and so can be used unchanged. Some aspects (such as the ability to identify a voter easily) are required in some scenarios but prohibited in others, so EML defines them as optional. Where they are prohibited, their use must be changed from an optional to prohibited classification, and where they are mandatory, their use must be changed from an optional to required classification. The technical approach to achieving this is described...

The UK is an early adopter of EML. Work on identifying the additional constraints for UK local elections has identified several areas in which version 2 of EML does not meet current requirements. This document therefore also proposes changes to the base EML language. These changes will be adopted in the UK and proposed to the international committee for adoption in a later version of EML.

From the specificatopn "EML Message Validation":

The combination of the EML schemas, APD schemas [Address and Personal Details Schema], the revised EML externals schema and the Schematron schemas provides the normative definition of the messages to be used in this application. This provides a clear separation between the international EML specifications and the additional constraints used for UK local elections.

Note that the EML externals schema references the APD schemas assuming they are all in the same directory. For validation to work, either the schemas must be placed in the location expected or the path changed in the EML externals schema.

It is up to each specific system implementation whether it uses these schemas for validation of EML messages for either testing or live use. The recommended approach is to validate incoming messages against the EML schemas (with the application-specific EML externals schema), then further validate against the relevant Schematron schema. The first stage requires the use of an XML processor (parser) that conforms to W3C XML Schema. The second stage requires an XSLT processor.

However, an implementation may choose to: (1) modify the EML schemas to incorporate those application-specific constraints that can be represented in W3C XML Schema; (2) not validate these changes; (3) not perform any validation; or (4) develop some alternative validation.

However, one purpose of the pilots over the next few years is to test both EML and this mechanism of customisation. The Office of the e-Envoy will welcome feedback on the use of this mechanism.

About the OASIS Election and Voter Services TC:

The purpose of the Election and Voter Services Technical Committee is to develop a standard for the structured interchange of data among hardware, software, and service providers who engage in any aspect of providing election or voter services to public or private organizations. The services performed for such elections include but are not limited to voter role/membership maintenance (new voter registration, membership and dues collection, change of address tracking, etc.), citizen/membership credentialing, redistricting, requests for absentee/expatriate ballots, election calendaring, logistics management (polling place management), election notification, ballot delivery and tabulation, election results reporting and demographics."

The principal goal of the committee is to develop an Election Markup Language (EML). This is a set of data and message definitions described as a set of XML schemas and covering a wide range of transactions that occur during an election. To achieve this, the committee decided that it required a common terminology and definition of election processes that could be understood internationally. The committee therefore started by defining generic election process models.

These processes are illustrative, covering the vast majority of election types and forming a basis for defining the Election Markup Language itself. EML has been designed such that elections that do not follow this process model should still be able to use EML as a basis for the exchange of election-related messages.

EML is focussed on defining open, secure, standardized and interoperable interfaces between components of election systems. Thus providing transparent and secure interfaces between various parts of an election system. The scope of election security, integrity and audit included in these interface descriptions and the related discussions are intended to cover security issues pertinent only to the standardised interfaces and not to the internal or external security requirements of the various components of election systems.