title: Causality and causal inference in epidemiology: the need for a pluralistic approach.
abstract: Causal inference based on a restricted version of the potential outcomes approach reasoning is assuming an increasingly prominent place in the teaching and practice of epidemiology. The proposed concepts and methods are useful for particular problems, but it would be of concern if the theory and practice of the complete field of epidemiology were to become restricted to this single approach to causal inference. Our concerns are that this theory restricts the questions that epidemiologists may ask and the study designs that they may consider. It also restricts the evidence that may be considered acceptable to assess causality, and thereby the evidence that may be considered acceptable for scientific and public health decision making. These restrictions are based on a particular conceptual framework for thinking about causality. In Section 1, we describe the characteristics of the restricted potential outcomes approach (RPOA) and show that there is a methodological movement which advocates these principles, not just for solving particular problems, but as ideals for which epidemiology as a whole should strive. In Section 2, we seek to show that the limitation of epidemiology to one particular view of the nature of causality is problematic. In Section 3, we argue that the RPOA is also problematic with regard to the assessment of causality. We argue that it threatens to restrict study design choice, to wrongly discredit the results of types of observational studies that have been very useful in the past and to damage the teaching of epidemiological reasoning. Finally, in Section 4 we set out what we regard as a more reasonable 'working hypothesis' as to the nature of causality and its assessment: pragmatic pluralism.
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands and Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jan P
authors.initials: JP
authors.lastname: Vandenbroucke
authors.affiliation: Department of Philosophy, University of Johannesburg, Auckland Park, South Africa.
authors.forename: Alex
authors.initials: A
authors.lastname: Broadbent
authors.affiliation: Department of Medical Statistics and Centre for Global NCDs, London School of Hygiene and Tropical Medicine, London, UK and Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors.forename: Neil
authors.initials: N
authors.lastname: Pearce
mesh_terms: D015984:Causality; D004813:Epidemiology / Q000592:standards*; D006801:Humans; D008962:Models, Theoretical; D010684:Philosophy; D015203:Reproducibility of Results; D012107:Research Design; D018570:Risk Assessment; D012307:Risk Factors