I thought this article was interesting:
I also like this rational wiki:
a few quotes:
"Correlation does not imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing "look over there." "
"In science, correlation studies are often used to test for the existence of interesting patterns, but they are never used exclusively to claim a cause. In order to make a causal claim you must run an experiment or series of experiments and further studies using the scientific method— i.e., test to see if it really is a cause by altering parameters and performing more experiments, making predictions and testing them. This is in order to validate that one event is indeed directly influencing the other and is the reason behind the detected correlation."
To me , it sounds like causation is a pretty high order. Only things that are scientifically proven (perhaps repeatedly) can show causation. Vaccine studies are usually done by pharmaceutical companies - they are not interested in doing studies to show that certain correlations might indeed be causation. As such, correlation is sometimes all we have. It is certainly all we have until (if) scientists decide to try and figure it out.
That smoking causes lung cancer first started out as a correlation. It was a correlation that was noted throughout the globe, a correlation that was repeatedly noted. It took decades from the moment people first noticed a correlation until it was accepted as a causation. http://toxsci.oxfordjournals.org/content/64/1/4.full
I am not saying vaccine are to certain pediatric health issues what smoking turned out to be lung cancer - but I will say it will take years for people to sort out, if they even try…and in the mean time all we have is correlation which is not nothing.