Digital devils response
Thursday, July 16th, 2009Bernd Beber has responded to my (and others’) criticisms of his article on suspected Iranian election fraud authored with Alexandra Scacco. An annotated and updated version of the article is available.
A key criticism leveled against Alex Scacco’s and my Washington Post op-ed on the election in Iran is that we argue that a fair election is unlikely to produce a lot of variation in last-digit frequencies, but then use an inappropriate test in evaluating the data from Iran against this claim. We should have reported the results from a chi-square test, not the probability of particular digits occurring more or less often than expected.
Is a chi-square test the most appropriate statistic for this type of data? Yes. That’s exactly why we report the result in the annotated version of our op-ed. (We initially reported only a nearly equivalent test statistic involving the standard deviation of last-digit frequencies, but since then we’ve clarified that this is the same result one obtains from a chi-square test.)
But is this test the most appropriate one for a general audience? Only if there isn’t a more transparent alternative that captures the same intuition and gives the same substantive result. In our view, the test statistic we report is precisely such an alternative.
