Why Do Acquarians and Geminis Differ About the Efficacy of Bone Marrow Transplants?
Let's say that you had chronic myeloid leukemia (CML) and that your doctor recommended a bone marrow stem cell transplant. Let's also say that you decided to check out the literature so as to be better informed. When you did you found that in a well designed study of 626 CML patients a large and highly statistically significant difference in risk of death from the procedure was revealed. Indeed, those transplant patients with the astrological sign of Aquarius were likely not to die in the following 5 years whereas those born under the sign of Gemini had a much greater risk of death and in fact were more likely than not to die within 5 years of the procedure. Finally, let's say that you are, in fact, a Gemini. Do you go ahead with the transplant?
Ok, ok. Before you make up your mind you go looking for other papers published in respected peer reviewed journals that look at zodiac sign and medical treatments. Guess what? You find other papers also showing that your sign is associated with a statistically significant increase in risk of injury or death! Now what?
Well, the first thing you need to remember is if you're dredging data for statistically significant associations and you don't find any, well, all that proves is that you don't know what you're doing. Epidemiology works when you formulate a hypothesis and then test it. When you go dredging for data without having in hand a hypothesis to be tested, knowing that the laws of probability will invariably generate statistically significant yet spurious associations, you're just manufacturing "science"; discovering nothing and flaunting the scientific method in the process.
For a fun read about why Geminis ought not worry about their sign and how statistically significant associations, based on the most rigorous statistical analyses, can be be generated at will to support, if that's the word for it, the most absurd causal inferences read: "Sign of the Zodiac as a Predictor of Survival for Recipients of an Allogeneic Stem Cell Transplant for Chronic Myeloid Leukaemia (CML): An Artificial Association".
