Correlation is not the same thing as causation.
This is one of the biggest things misunderstood (or deliberately ignored) about a great many things, guns being one of them...
It is a virtual certainty that 99%+ of all convicted felons in the US ate bread, or a bread product within 30 days of committing a crime.
This is a correlation. Something that is connected to something else, and can be proven.
"Ban bread, because bread causes crimes!"
This is based on the assumption that a correlation is a cause. And obviously a false assumption in this case.
personally, I think we spend too much money and effort doing studies and acting on our perception of their results. I'm beginning to wonder if we shouldn't be adding "studies indicate..." to the list of big lies (which include "the check is in the mail", and "we're from the govt and we're here to help you", among others... ).
We get all happy when studies show things our way (and when they actually do accurately reflect reality-which is usually the same thing
but remember that studies "proving" us right can be as flawed as one's showing us we're wrong...