Abstract:
During excavation for an industrial park, hazardous wastes, including known carcinogens, are discovered in Woburn, Massachusetts. At the same time, two town wells are taken out of service because of chemical contamination. A local minister becomes aware of what seems like an unusual concentration of leukemia and agitates for government action. The state's Department of Public Health embarks on an epidemiological study which turns up statistically significant excess cancers of two types, but it cannot establish an association between these cancers and any environmental phenomenon. How should DPH describe its "findings" to the public? What should it do next? Part A covers the issue up to the release of this initial investigation. Part B deals with the aftermath of these findings and the subsequent study of past mortality rates from childhood leukemia and kidney cancer in Woburn.
Learning Objective:
This case highlights: (1) the differences between the various meanings of "significant"; (2) the poignant dilemma of a public that expects simple answers and guidance from its government ("Is it safe or isn't it?") but presumably wants professional standards of inference and research protected; and (3) the difference between drawing conclusions according to an arbitrary confidence standard and drawing them under pressure to take some action. It presents the common problem of balancing the public's right not to have to be an expert in technical matters against the irreducible complexity and uncertainty of data-poor but causally complex policy problems.
