Regarding bias.

Fibre type and burden in parenchymal tissues of workers occupationally exposed to asbestos in the United States. In: Non-occupational exposure to mineral fibre and patterns of asbestos-related disease in chrysotile miners and millers. Asbestos exposure dose-Broncho-alveolar milieu response in asbestos workers and the sheep model: evi-dences of a threshold for chrysotile-induced fibrosis. In a recent editorial, "Media and Science: Harmless Dioxin, Benign CFCs, and Good Asbestos" (EHP 102:10), David P. Rail decries the "mistakes in editorial policy and reporting" in science and medicine, and suggests "balancing controversial views in the same issue and to invite letters and commentary for publication in the same issue" of the journal in which the material is published. He dealt with "serious environmental concerns: dioxin, chlorofluoro-carbons (CFCs), and asbestos." In regard to the dioxin story in particular , Rail quoted from the Fingerhut (1) report that "workers exposed to dioxin for more than 2 years and observed for at least 20 years had a 46% greater cancer death rate than expected." This article was accompanied by an editorial which many newspapers quoted at the time of the report, and others did not, as Rail chose not to. The editorial, written by Bailar (2), notes that "Results are again equivocal. Parties on both sides of the continuing debate about the regulation of dioxin exposure will no doubt cite this work in support of their positions" (as I am doing, and as Rail did, by not citing the editorial). Bailar continues: Some cancers were indeed more frequent in an exposed group than among controls, but the differences were for the most part not statistically significant , and the exceptions might be explained by a combination of small, unavoidable biases in the data and the multiple post hoc comparisons. (Examine enough data at the usual 5 percent level of significance and about 1 time in 20 you will find a statistically significant result where there is no real effect.) The information is there, but depending on the reporter, the newspaper, or the scientist you will inevitably get a different story. Following the Fingerhut article, for example, one newspaper headline read "Chronic Dioxin Exposure ups Cancer Risk," another read "More Research into Dioxin Urged," and still another "The Deadliness of Dioxin Put in Doubt By New Data." Rail also states that "A 10-year follow-up of those exposed to dioxin after the chemical explosion at Seveso in 1976, published in …