Bellmanism: the distortion of reason.

Single-issue compound or class related anxieties about chemical exposures are often the focus of concern for groups that seek to affect the regulatory process itself or the regulatory status of compounds that have passed through it. A characteristic of these groups is an imperfect understanding and use of science, in particular in the evaluation of data. Studies which have been discredited are cited repeatedly and the role of confounding factors is not generally acknowledged. The regulation of medicines, devices, pesticides and some household chemicals depends on the use of a methodology that follows strict protocols. This involves testing in many systems including mammals, other vertebrates, invertebrates, soil macrobiota or ground water, as examples, with often well-defined schemes of interpretation which facilitate extrapolation between species. A complex risk evaluation will then be made for different groups (by age, sex, or occupation, say) or targets (patients, farmers, consumers and vulnerable non-human species). Focusing on an effect in a single group may suggest interventions which will be damaging for others.