The project used the Ontology development 101 methodology 22 and the open source Protégé ontology-building software (from Stanford University 23 ) as the development tools. Ontology development 101 and Protégé were selected after a scan of available methods and software, because they were considered to be the most useful tools for the work, are openly available (i.e. do not require a commercial license), provide support for emerging Semantic Web standards, and have active communities of interest with strong representation from researchers and knowledge workers in health, biomedical and other related fields.