The end of the use of leaded gasoline may be the cause of the fall of violent crime
over the past 25 years. Epidemiological research linking lead exposure in small
children with myriad complications later in life , including lower IQ , hyperactivity ,
behavioral problems , and learning disabilities , suggested a link between childhood
lead exposure and juvenile delinquency later on. Had lead exposure an effect on
violent crime also ?
With correlation factors ~0.90, I'd have to say that causation is indisputable.
New Orleans' violent crime rates and firearm deaths are the highest in the US, in accord with the lead exposure levels.
Several bills before Congress seek to relax standards on tetraethyl lead use. Far be it from me to label these bills' sponsors as dangerous
psychopaths requiring permanent censure.
I would believe your argument more if you examined the crime rates in Boston over time. This city instituted smart programs (after school study,
lunch, summer programs,...) which reduced crime. If lead exposure was about the same as a peer of other cities where crime rates remained unchanged,
your hypothesis is void.
[Edited on 3-2-2013 by AJKOER]AndersHoveland - 3-2-2013 at 18:52
Lead exposure is only one factor, there are others also...franklyn - 6-2-2013 at 08:26
Do you think 'phone ownership causes fuel use or is the causation the other way round?
It's easy to play this game, find two values that both have a tendency to trend with a third value- time is usually the easiest)- then plot them
against eachother and calculate the correlation coefficient.
Here's a similar joke http://xkcd.com/925/
Now imagine what plots of crime rate vs poverty and lead exposure vs poverty would look like.
I dare say lead exposure has an effect but I think other effects are bigger
