The "at risk" register: a statistical evaluation.

In the past decade there has been considerable discussion about the policy of the early selective screening of children at high risk of suffering from handicapping conditions which are not apparent at birth. This policy was advocated by Lindon (1961) and Sheridan (1962), who felt that universal screening of all infants was not practicable at that time. Sheridan in particular considered that it was essential to keep children 'at risk' under surveillance until their development was seen to be progressing entirely normally. They recommended that local authorities kept 'At Risk' registers of vulnerable children, and this recommendation was reiterated by the Sheldon Committee Report (Ministry of Health, 1967) and by a working group of the World Health Organisation (1967). Nevertheless in 1967 Oppe and Walker, who reviewed the functioning of such registers in the U.K. and Scotland respectively, found that the detection rate based on selective screening was disappointing (Oppe, 1967; Walker, 1967). They attributed this largely to the difficulty of defining precisely the factors which put an infant 'at risk'. This tended to make the registers longer and longer, in some authorities comprising as many as 60% of all live births, thus negating the advantages of selective screening. Other authors confirmed the disappointing results of the 'at risk' policy and criticized the concept itself as being inherently unsound (Richards and Roberts, 1967; Rogers, 1967; Hamilton, Richards, Barron, Mackie, and Finlayson, 1968). Forfar (1968) also felt that selective screening was not a satisfactory substitute for universal screening but considered that the 'at risk' register should be retained as an additional safeguard. The critics of the concept of selective screening based their arguments largely on the fact that no local authority has managed to achieve the goal forecast by Lindon (1961) namely, that the screening of a small group, 10 to 20% of all births, would identify the majority of those with 'invisible' handicaps. However, to our knowledge there has been