Journal of Clinical Epidemiology 55 (2002) 1–4 0895-4356/02/$ – see front matter © 2002 Elsevier Science Inc. All rights reserved. PII: S0895-4356(01)00428-0 COMMENTARY On not taking the world as you find it—epidemiology in its place Anthony R. Mawson* Visiting Professor of Public Health and Director, Institute of Epidemiology and Health Services Research, School of Allied Health Sciences, Jackson State University, 350 West Woodrow Wilson Avenue, Suite 2301-B, Jackson, MS 39213, USA Received 15 May 2001; received in revised form 19 July 2001; accepted 24 July 2001 Abstract Modern epidemiology has been criticized as being fragmented and reductionist, lacking coherent theories, and contributing little to the under- standing of disease. These criticisms assume that epidemiology is a system of knowledge about health and disease, based on observation. In fact, consensus on the definition of the field is surprisingly elusive. A more practice-based approach would be to consider epidemiology as a field con- cerned with the methods for determining the causes of disease and for evaluating health services and treatments. The value of epidemiology is that it provides the tools for doing well-crafted research once the substantive hypothesis has been formulated. The focus of the discipline is thus method- ological rather than conceptual. The major implication for the practitioner is that he or she must necessarily be more than an epidemiologist. Theoret- ical understanding must come from conceptual developments in the substantive fields of medicine, sociology, or biology and, more fundamentally, from fresh visions that transcend traditional categories of exposure and disease and accepted views of causation. © 2002 Elsevier Science Inc. All rights reserved. Keywords: Epidemiology; Medicine; Health; Disease; Methods; Theory 1. Introduction Many recent commentators have been critical of epidemi- ology. The discipline is said to be fragmented, isolationist, and reductionist [1,2]; different levels of research and analy- sis need to be integrated [3,4]; epidemiologists need exten- sive retraining; and more work needs to be done at the popu- lation level [5,6]. Modern epidemiology has also been criticized—unfairly—as lacking a coherent, substantive the- ory, and as having contributed little to knowledge of the etiol- ogy and mechanisms of disease [7–13]. The latter criticism is misplaced because it falsely assumes that epidemiology is a science based on observation, when it is better understood as a methodological enterprise for disentangling cause-and- effect relationships. The problem lies not in epidemiology per se, but in the state of biomedical knowledge and perhaps in the training of epidemiologists. Ironically, the field of epide- miology is thriving, and the need for it is growing. However, research aimed at understanding disease should have as its primary focus the observations that need to be explained, not methods, and this requires substantive knowledge that goes beyond methodology itself. Knowledge and sound methods are both vital for understanding diseases, but so are the inves- tigator’s vision, intuition, and imagination. Historical exam- ple shows that significant research is done not by taking the world as one finds it, but by viewing it differently, by the dis- ciplined use of creativity and imagination, and a willingness to challenge accepted categories and models of disease. 2. Definitions of epidemiology How one defines the field of epidemiology has important practical implications for assessing its strengths and limita- tions, yet consensus on the definition is elusive. One defini- tion that is historically accurate is the study of epidemics. Dis- ease epidemics have formed a major part of the history of medicine and public health. Indeed, if one opens any text- book of epidemiology there will usually be a discussion of John Snow’s [14] famous study of cholera in London, and the story of the removal of the handle of the Broad Street pump—an act often credited, erroneously, with ending the epidemic. Yet detailed descriptions and analyses of specific epidemics are typically lacking in the textbooks. A second definition—studies on the people—derives from the literal meaning of the word epidemiology and its compo- nents: epi (on), demos (people), and -ology (Greek, for the study of) ([15], p. 1). However, epidemiology textbooks de- vote little space to people (or health, or even disease). The study of people is the domain of the social sciences. * Corresponding author. Tel.: 601-979-1102. E-mail address: armawson@aol.com (A.R. Mawson)