An Exercise in Surveying a Non-Universally Defined Group in the Population: The Northern Ireland Survey of Activity Limitation and Disability (Survey‪)‬

1. BACKGROUND At its most objective level disability is a continuum, a line along which everyone in a population can be placed. However, an individual's position on this line is likely to change over their lifetime. Additionally, their position at any one point in time is not necessarily clear. At one end of the line is a group of individuals whom most people would agree are not disabled. At the other end of the line is another group of individuals about whom there would be general consensus that they are disabled. However, between these two extremes lies a third and potentially sizeable group, constituting people whose classification is more ambiguous and is effectively a matter of judgement. This lack of clarity of definition raises many issues when social scientists are asked to provide hard evidence and authoritative data upon which to develop and assess policy and service provision for people with disabilities.