by Nicholas Beaudrot of Electoral Math
TNR's Noam Schieber writes, "the margin of error for the likely-voter portion of the poll, where Obama leads Clinton by 4 points, is plus or minus 7--i.e., Obama's lead is statistically meaningless." Not true! A 7% margin of error means that there is a 95% confidence that a candidate's true level of support is within 7% of the reported value. In practice, if the pollster's screen of likely caucus-goers is accurate, it means that among likely caucus-goers there's a 67% chance that Obama is ahead. Good odds, but not a mortal lock.
Kevin Drum produced this table that can help you read the polls.
