This paper focuses on a context where interdisciplinarity intersects with interprofessionality: the work of children's services professionals who address the needs of children identified as vulnerable. It draws on evidence and perspectives from two disciplines — educational studies and health care — to consider the issues and challenges posed by learning and/or working across disciplinary boundaries and why these have proved so obdurate.

In 2002, the Qualifications and Curriculum Authority (QCA) published the report of an independent panel of experts into maintaining standards at Advanced Level (A-Level). One of its recommendations was for: 'limited experimental double marking of scripts in subjects such as English to determine whether the strategy would significantly reduce errors of measurement' (p. 24). This recommendation provided the impetus for this paper which reviews the all but forgotten literature on double marking and considers its relevance now.