Correlation does not mean causation.

I see people forgetting this all the time. I have thought about writting a short piece on it, and I have pushed it off again and again simply because it is not that much fun of an article to write. I mean the old example of "100% of people who drink water die" should be enough it show why just because there is a very strong correlation between two things ( drinking water and dying) it in no way means that drinking water causes death.

A harder concept may be what exactly is correlation? I think most people understand that it means some sort of relationship between two factors. On her blog Moved by Metrics my friend,Georgette Asherman, does an excellent post exploring the concept of Correlation.

Another blog I often read is Falkenblog. He usually does posts on fairly serious issues and financial matters. Not today! Today when I go this his site, it is a post with a link to a site that posts unusual correlations. I click it and the first one is the correlation between people who dislike mayonnaise and bad dancing. I am dying laughing because I hate mayonnaise and I am a terrible dancer. If you need a quick smile during the day go to correlated.org.