No Causality Implied - Post 1

I’m starting a new reoccurring post called No Causality Implied. I got the idea from a funny picture I saw a week or so ago when everyone was talking about the Somalian pirates.

The picture implies that the decline in the number of pirates is somehow related to change in the global temperature. Awesome. As everyone who has taken a statistics class learns, this is a common mistake when looking at data and can lead to (accidentally or deliberately) improperly interpreted data.

What better way to kick this off than by quoting the greatest TV show ever, The Simpsons. I won’t bore you with the details, but in one episode someone says “have you ever noticed the correlation between the decline in Spirograph and the rise in gang violence?” I was able to find data about the number of gangs in Los Angeles going back to the late 60’s (Spirograph was created in 1965 and release in the US in 1966). Then I went to ebay and counted the number of Spirograph pieces available from 1967 to the present (a toy produced in 1967 was counted as 1 for 1967 and a toy produced in 1996 was counted as 1 for 1996) and then I grouped the data to match the years I had for gang data. Amazingly, you can see the correlation between the decline in Spirograph and the rise in gang violence. I promise that I did not manipulate this data.