Causation and Hill’s Criteria

[n2doc]

Published by Mark Crislip under Science and Medicine

Causation is not so simple to determine as one would think. A mantra at SBM is ‘association is not causation’ and much of the belief in the efficacy of a variety of quack nostrums occurs because improvement occurs after use of a nostrum, therefore improvement occurs because of use of a nostrum. It is why vaccines as a cause of autism are so compelling to some. Vaccines are given at the same time autism starts to manifest. It would require more intellectual power than I have not to conclude, wrongly, that vaccines caused the autism. Concluding causation from sequential events is how the human mind works, and reality, as we know and ignore, constantly conspires to fool us into making false causal connections. In Infectious Diseases I see the error almost daily. The patient had a fever, patient was given antibiotics, fever went away. Therefore the antibiotics treated an infection. Well, maybe, maybe not. One of my mantras is ‘antibiotics are not antipyretics’ and you must be very careful before concluding that the fever went away because of the penacephalone.

I blog and podcast in large part to educate myself. It is amazing how much I learn in the process of preparing for one of the entries in my multimedia medical empire. Areas of knowledge that I had no idea existed can be revealed for exploration. I do not have formal training in epidemiology, although part of my job is hospital epidemiology. Like much of medicine, I acquired what I do know from on-the-job training and lots of reading. So imagine my surprise and delight to discover Hill’s Criteria of Causation, thanks to its application to chiropractic subluxation.

In 1965, Austin Bradford Hill published “The Environment and Disease: Association or Causation?” Dr. Hill, an occupational physician, sought to answer the questions (another discussion of the paper here):

How in the first place do we detect these relationships between sickness, injury and conditions of work? How do we determine what are physical, chemical and psychological hazards of occupation, and in particular those that are rare and not easily recognized?…In other words we see that the event B is associated with the environmental feature A, that, to take a specific example, some form of respiratory illness is associated with a dust in the environment. In what circumstances can we pass from this observed association to a verdict of causation? Upon what basis should be proceed to do so?

more:

http://www.sciencebasedmedicine.org/?p=3254

[HuckleB]

1. K & R.