While mythical numbers will always circulate at warp speed, on the Internet the corrections often circulate almost as fast — unlike the mainstream media who often ignore their errors (unless forced to acknowledge them by the growing new media).
Along the same lines, this exercise is another reminder that even responsible officials, responsible newspapers, and responsible research groups pick up and pass on as gospel numbers that have no real basis in fact. We are reminded by this experience that because an estimate has been used widely by a variety of people who should know what they are talking about, one cannot assume that the estimate is even approximately correct.
(1) “High Speed Rail Proposals Map“, Matthew Yglesias, ThinkProgress, 21 April 2009 — There is no point reading the “cost be dammed” thinking from a young leftist journalist, the graphic is nifty — and this comment provides the perfect response. By Rich in PA: