When a contributor has written or edited a work “on behalf of” an organization or group, the contributor is acting as a representative of the organization, which may or may not be his/her usual affiliation.
Some DTDs identify this category as a Collaborative (Group) Author <collab>, but it is really more akin to a “role” the person is playing with respect to the organization. Thus, this element joins the related element <role> in describing the contribution of a contributor. The <role> element will say that a person is an “Editor” or “Associate Editor”, and the <on-behalf-of> element will state that this editing was undertaken as a representative of a group or organization:
<on-behalf-of>for the Multiple Sclerosis Collaborative Research Group</on-behalf-of>
Any combination of:
... <contrib contrib-type="author"> <name> <surname>Forster</surname> <given-names>Anne</given-names> </name> <on-behalf-of>for the Multiple Sclerosis Collaborative Research Group</on-behalf-of> <role>research physiotherapist</role> <xref ref-type="aff" rid="StLukes"> <sup><italic>a</italic></sup></xref> </contrib> </contrib-group> ...