The nature of medical wisdom, with the here-today-gone-tomorrow nature of its recommendations, is controversial to say the least. Many explanations have been offered to make sense of why recommendations that are made with confidence this year are later refuted and reversed.
One of the simplest explanations is that this is the natural rhythm of science. An observation leads to a hypothesis. The hypothesis is then tested, and usually fails, which is always the most likely outcome in any scientific endeavor.
Why is that so?
Quite simply because there are an infinite number of wrong hypotheses for every right one. Therefore, the odds are always against any particular hypothesis being true, no matter how obvious or vitally important it might seem in the beginning.
The seesaw effect is often caused by the interplay between observational studies and clinical trials.
The catch with observational studies is that they cannot conclude that one event causes the other. They can only provide hypothesis-generating evidence, which in a court of law would amount to circumstantial evidence. Observational studies are then often followed up with randomized-controlled clinical trials, essentially an experiment, which typically results in the flip-flop rhythm of medical wisdom, when the experiment doesn’t show the same result.
According to a 1994 editorial by Jerome Kassirer and Marcia Angell, two editors from The New England Journal of Medicine, “The problem is not in the research but in the way it is interpreted for the public.” Each study is just a piece of the puzzle and so the media needs to do a better job of communicating the many limitations and caveats involved, perhaps most importantly the fact that “an association between two events is not the same as a cause and effect.”
New York Times September 16, 2007