It's important to read the original blog post: http://gregmankiw.blogspot.com/2009/08/least-surprising-correlation-of-all.html http://gregmankiw.blogspot.com/20

It's important to read the original blog post: http://gregmankiw.blogspot.com/2009/08/least-surprising-correlation-of-all.html http://gregmankiw.blogspot.com/2009/08/least-surprising-corr... The author makes it quite clear there, but not in the sharing of this second graph, that the correlation does not imply a causation.