Controversy in the detection of disease.

The quality of discussions and debates into the proper roles for screening, case-finding, diagnosis, and epidemiological surveys in the detection of disease will be improved when participants use consistent definitions, understand the different purposes and properties of the manoeuvres, recognise ideological differences between advocates and methodologists, and consider the quantitative and qualitative differences between decision making for the individual patient and decision making for the community. Although attention to these causes need not detract from the colour of the continuing controversy, it should render the exchange more comprehensible to participants and spectators alike.