Epidemiology is concerned with the distribution of disease or physiological conditions in human populations and the factors that influence their distribution. Popular epidemiology, therefore, refers to when the lay public does work that is traditionally done by corporations, experts and officials. This can involve citizen-propelled investigations of naturally occurring diseases for which no firm is responsible. However, popular epidemiology is usually employed in cases of environmental pollution or occupational disease. In some cases, the persons and organisations responsible may have knowledge about the dangers to the public health, but do not act due to vested interests. The process of popular epidemiological investigation is therefore one of activism, in which epidemiological findings are immediately employed to understand the causes of community health problems and alleviate suffering or also to ask for compensation for liability. For instance, have cancer-related deaths due to pollution escaped the official medical surveys? How would one count the cases of illness caused by Chevron-Texaco practices in the Amazon of Ecuador between 1970 and 1990 in areas without doctors? (San Sebastian and Hurtig, 2005). Environmental health activists are by definition acting to correct problems that are not addressed by established corporate, political and scientific communities.
The cases of ‘popular epidemiology’ that arose in the Environmental Justice movement in the United States, and similar cases elsewhere, teach several important lessons regarding the relationship between scientific rigour, human health and the assessment of uncertainty. Firstly, they show the value of popular epidemiology in the detection of environmental risks. This is because people have access to data about themselves and their environment that is not available to scientists (disappearance of animals, health problems, bad odours, etc.). Citizens who feel they may be at risk may also react more quickly than authorities and their involvement makes studies possible that would not otherwise be due to lack of money and personnel. For example, some methods of lay detection can be as simple as setting up a hotline to report health problems, while government studies need time to mobilise financial resources.
Epidemiology carried out by affected communities and scientists may also differ regarding the burden of proof and the direction of proof. For example, in science, we may consider two types of errors:
• Type 1 error: (not finding a relationship when it exists)
• Type 2 error: (finding a relationship when it does not exist)
For a scientist, a Type 2 error is more damaging to his reputation. However, when investigating whether toxic chemicals harm the environment, privileging Type 1 errors over Type 2 errors is at odds with the public health concerns of communities. A community is, therefore, more likely to apply the precautionary principle, opting to err towards proof that there is no harm rather than waiting to prove harm without a doubt.
Finally, popular epidemiology raises the issue of value neutrality in science. In cases of responsibility for environmental health, there is often a trade-off between economic growth and the health of the community or the environment. Government or corporate scientists may not necessarily value these two variables in the same way as the affected community. Furthermore, while science claims to be value neutral and objective, studies in the field cannot be compared to studies in a laboratory. In real life situations, health impacts can easily be attributed to other factors, such as lifestyle choices, such as smoking. Corporate and government actors will thus magnify the inherent uncertainties in an effort to avoid liability.
The corollary of popular epidemiology is the precautionary principle, which aims to shift the burden of proof from exposed communities onto producers and distributors of toxic waste and to implicitly prioritise democratic over private interests in an attempt to pre-empt harm to the environment and humans. Until this is put into practice, popular epidemiology remains a valuable tool for communities dealing with risks to their health and environment.
San Sebastián, M., & Hurtig, A. K. (2005) Oil development and health in the Amazon basin of Ecuador: the popular epidemiology process. Social science & medicine, 60(4), 799-807.
For further reading:
Brown, P. (1992) Popular epidemiology and toxic waste contamination: lay and professional ways of knowing. Journal of Health and Social Behavior, 267-281.
Novotny, P. (1994) Popular epidemiology and the struggle for community health: Alternative perspectives from the environmental justice movement. Capitalism Nature Socialism, 5(2), 29-42.
This glossary entry is based on a contribution by Leah Temper
EJOLT glossary editors: Hali Healy, Sylvia Lorek and Beatriz Rodríguez-Labajos