I keep running across different statistical analyses of the Palm Beach voting and hand re-count that try to make the case that Bush or Gore is trying to steal the election. Unfortunately I have yet to see one that wasn’t just garbage.
A few days ago, for example, Slashdot linked to an MIT statistical analysis that compared the ratio of Buchanan voters to Bush voters by county. Of course the effect of the resulting graph made it look “obvious” that the Buchanan votes had to be in error. The only problem is, as one Slashdotter noted, there is no scientific reason for choosing to compare Buchanan’s votes to Bush’s votes and comparing say Buchanan’s vote to average rainfall or the number of Britney Spears songs played on local radio stations. The Buchanan:Bush ratio appeared to have been chosen because it would produce the most dramatic graph.
Similarly, a statistical analysis of the hand re-count by Bruce Borders on the conservative FrontPage.Com site argues that re-count disproportionately favored Gore. I was very intrigued by this until I read the following paragraph,
In large democratic leaning counties, the percentage change in votes was significantly larger for Al Gore than for George W. Bush. In these counties (Broward, Miami-Dade, Orange, Palm Beach and Pinellas) the percentage increase in votes for Al Gore is approximately 9 times greater than the percentage increase in votes for George W. Bush (0.068% increase for Gore vs 0.0077% for Bush). This is a statistically significant difference at the 0.108 level of probability – this means that we are approximately 90% confident that we are drawing the correct conclusion.
The last sentence is what makes me think this analysis is bunk. Although I have no probability data, for the most part people who report statistically signficant results at 90% confidence level are doing so because they know that if they report results for the 95% confidence level, which is a widely accepted level of confidence, the results no longer are meaningful.
Pharmaceutical companies are notorious for this. Got a drug that doesn’t seem to work all that well when work out the results at a 95% confidence level? No problem — just redo the statistics for a 90% confidence level and hope nobody notices.
A 1 in 10 chance that the results are due entirely to chance is pretty darn high given the seriousness of the claim.