“Epidemiology is concerned with the incidence of disease in populations and does not address the question of the cause of an individual’s disease. This question, sometimes referred to as specific causation, is beyond the domain of the science of epidemiology.” — Freedman DM Green, MD, Freedman and L Gordis, Reference Guide on Epidemiology, National Research Council
“Even the most rigorous epidemiological studies suffer from a fundamental limitation. At best, they can show only association, not causation. Epidemiological data can be used to suggest hypotheses but not to prove them. … Epidemiological studies, at their best, can only point out a possible connection between two things, but that is only the very first step in trying to figure out whether or not there really is a connection between them.”
— Georgia Ede, MD
“Epidemiological studies provide a valuable tool for the investigation of the causes of disease. However, such studies alone are rarely able to prove cause. No study is perfect and the evaluation of results must take account of the design and execution of the study together with the analytic methods used.” — Richard Farmer, Department of Epidemiology, University of Surrey, UK
“In theory, [epidemiological] research should be driven only by a desire to establish the truth. However, in the real world, other factors often interfere with this aspiration and can result in conflicts of interest. Research has to be funded, carried out and ultimately published, whilst researchers seek to promote their reputations and careers. Research is, therefore, often carried out amidst many competing agendas.” — Helen Barratt and Maria Kirwan, Public Health Action Support Team and the UK Department of Health
Note: Epidemiology is a basic science, not an applied science. “Basic science increases the knowledge base of a field of research, while applied science uses that knowledge to solve specific problems.” Nearly all, if not all, of the studies conducted by the US government on the possible link between vaccines and autism have been epidemiological studies.
Courtesy: The Outliers