Much of the writing on differences in educational attainment by different social classes in Ireland has started by accepting the use of the tenn 'educational disadvantage' and trying to define it afterwards (Kellaghan et at., 1995; Boldt and Devine, 1998). Others, like Drudy and Lynch have simply dismissed the use of the tenns out of hand, preferring instead to write about social class differences in education (1993, p 52). Far from discouraging the use of the term, this latter sort of intervention seems to have had no effect and the use of the tenn has continued to proliferate in this decade. The tenn is now widely used by agencies from the Conference of Religious in Ireland (CORl) to the Combat Poverty Agency (CPA) to the Government of Ireland. It is used by researchers, teachers, policy makers and those who fund research. It appears that the tenn is here to stay. Despite a recent comprehensive review of research in the area (Boldt and Devine, 1998), it is still far from clear what is meant by educational disadvantage. In this paper I will look at the different definitions of educational disadvantage proposed. I will argue that the use of the tenn in Ireland has many similarities with the use of the tenn "at-risk" in the US and has similar problems. The at-risk model understands educational disadvantage as akin to a disease or a condition - it is something the individual has. I will argue that educational disadvantage should be seen as a series of active processes, rather than a condition. Such an approach to educational disadvantage has serious consequences for our attempts to research and to measure the phenomenon.