Democratic Underground - 'goodmath' missed the more glaring problem

A margin of error is measured to within a level of confidence. Most of the time, the MoE that we see cited is the MoE with 95% confidence. What this means is that 95% of the time, the sampled (polled) result is within that +/- n% range. But there is no case in which a result is impossible: the margin of error is an expression of how confident the poller is in the quality of their measurement: nothing more than that. Like any other measurement based on statistical sampling, the sample can deviate from the population by any quantity: a sample can be arbitrarily bad, even if you're careful about how you select it.

http://scienceblogs.com/goodmath/2006/06/election_fraud_or_just_bad_mat.php

This much is true, but the Stone piece actually passes a 68% confidence interval off as 95%:

Polls in thirty states weren't just off the mark -- they deviated to an extent that cannot be accounted for by their margin of error.

http://www.rollingstone.com/news/story/10432334/was_the_2004_election_stolen

Per RS's "Web-only citation" to NEP (p.5):

There were 26 states in which the estimates produced by the exit poll data overstated the vote for John Kerry by more than one standard error, and there were four states in which the exit poll estimates overstated the vote for George W. Bush by more than one standard error.

http://www.exit-poll.net/election-night/EvaluationJan192005.pdf

Plus or minus 1 standard error is a 68% confidence interval, plus or minus 2 standard errors is approximately a 95% confidence interval, and a 99% confidence interval is 2.58 standard errors on either side of the estimate.

http://en.wikipedia.org/wiki/Margin_of_error

Mark B. didn't point this out directly, but there seems to be a specific problem with RFK's first claim: he meant, or should have meant, that results in 30 states were off by more than one standard error, not by more than their "margin of error." Plus-or-minus one standard error is roughly half the conventional margin of error (a 95% confidence interval, roughly plus or minus two standard errors).

http://www.mysterypollster.com/main/2006/06/is_rfk_jr_right.html#comments

So "they deviated to an extent that cannot be accounted for by their margin of error" is false on two counts, like "Two Hindenburgs Explode, Helium to Blame"

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