Blog experts and amateurs

UCLA professor Mark A. R. Kleiman uses some pointed blogger critiques of New York Times columnist Paul Krugman and Chicago professor Daniel Drezner to make interesting points about the clash of expertise and amateur observation on the Web. Separately, Kleiman also gives a little tutorial on how to read media and political polls:

Being 4 points behind with a 5- point margin of error isn't being "essentially tied." It's being 4 points behind, plus or minus 5 points. That's a lot better than being 21 points behind, plus or minus 5 points, but I'd rather be ahead, thanks.

Of course, the reported margin of error reflects sampling error only, and ignores all the sources of systematic error. All it means is that, if I'd called another 465 people at the same time, using the same algorithm to select them, using the same weighting formula to adjust the sample to he assumed population of actual voters, and having the same interviewers ask the same questions, there's a 95% chance that the results of the second sample would have been within 5 points of the results of the first sample.

He's talking about Wesley Clark closing the gap on Howard Dean.