Brad DeLong says that Andrew Sullivan, like most reporters, is innumerate. This doesn’t surprise me at all, really. I know a lot of highly intelligent, overeducated people. Most are very good at words or numbers. Few are very good at both. While I did well enough in my stats classes and am at least conversant enough in numbers to be skeptical of bad reporting, I nonetheless quite often overlook obvious points and make errors such as Sullivan makes here.
Temple math professor John Allen Paulos has made a lot of money over the years writing on this general topic, including Innumeracy: Mathematical Illiteracy and Its Consequences (1989) and A Mathematician Reads the Newspaper (1995). I commend both to you. They’re written at a very intuitive level so that even a non-stats geek can get the point.