Radiation biology. Radioecology
ISSN: 0869-8031

Archives → 2020 → V. 60. №6. → pp. 565–594

Article

Hill’s Criteria “Experiment”. Counterfactual Approach in Non-Radiation and Radiation Sciences

A. N. Koterova, L. N. Ushenkovaa, and A. P. Biryukova

A.I. Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow, Russia

Abstract

The review formalizes, refines and extends the theoretical and practical aspects of the use of counterfactual concepts in non-radiation and radiation sciences. The essence of Hill’s causality criteria (Hill A. B., 1965) «Experiment», which is based on the «on contrary» approach and for epidemiology is the «natural experiment» is examined. It consists in observing the effect, the desired cause of which either decreases the intensity or is completely eliminated, regardless of the researcher (as opposed to controlled experiments in biology and medicine). This approach is called «counterfactual» in philosophy ( «counterfactual» is «contrary-thefact»). Hill called this methodology «the strongest support for the causality hypothesis». The philosophical meaning and history of counterfactual concept in the humanitarian disciplines (D. Hume, J. Newman, D. Lewis and others) are described. Data on the use of the counterfactual approach in epidemiology are presented (development of a special theory and methodology from 1980–1990s; S. Greenland, G. Maldonado and K.J. Rothman). A frequent replacement of the term «counterfactual» with surrogate and verbose explanations (Western and domestic authors; some international organizations) such as «Reversibility», «Stop/recovery studies», «Prevention», «Manipulation», «Reversibility» etc. It is concluded that it is advisable to replace these «artisanal» construction with the only unified term «counterfactual». The concepts of «counterfactual ideal» and «counterfactual contrast» are considered. In essence, these are synonyms, but there are differences in the practice of their application. The «counterfactual ideal» justifies the ideal control group when an individual or group of people exposed is compared with the same individual or the same group, but without exposure. Moreover – at the same time. Such an approach is actually impossible, therefore, substitution with real comparison groups is used, that is, controls ( «contrasts») imitating the «ideal». In this regard, the dualism of the term «counterfactual» can be observed: this is both a synonym for control or a comparison group (in experimental sciences), and a methodological approach based on eliminating the effect and then observing the effect (mainly in descriptive disciplines). In addition to examples of a counterfactual approach in general epidemiology, a number of relevant facts and scenarios from radiation epidemiology are considered. They are mainly associated with a decrease in carcinogenic effects with a decrease in the level of radiation exposure for one or another contingent (decrease in diagnostic and therapeutic doses, stiffening of radiation safety standards, etc.). These are groups of pregnant women irradiated in utero during fluoroscopy in the 1940–1960s, and children who underwent radiotherapy for noncancer pathologies in the 1920s – 1950s, and nuclear workers, radiologists, and some other contingents.

Keywords

causality criteria “Experiment”, counterfactual ideal, counterfactual approach in radiation epidemiology, exposure of children and in utero