zer0netgain wrote:
Now, that chart might have value in asking IF something about organic foods (or those that consume them) have some common factor which could be causing autism, but you're still covering a wide area of environmental factors.
Alternatively, you could ask if an uncharted factor was causing both the rise in autism and the rise in organic food purchase- that the rise in autism and the rise in organic food purchase are both effects of a cause that doesn't appear on the chart.
A famous example is that ice cream purchase correlates with crime. The more ice cream that is purchased, the higher the crime rate. But what is actually happening is that crime is highest during summer and so is ice cream purchase.
For purposes of this chart, (apologies to goldfish- or perhaps credit), you could theorize that enviromental toxins cause autism and also cause people to buy organic food to avoid the toxins. So rising autism and rising organic food purchase would both be effects of the cause that doesn't appear on the chart- enviromental toxins.*
*I'm not saying that I think enviromental toxins are why autism has gone up. But if I did think that, I could use this chart as "evidence".