Andrew Gellman solves the "nonpuzzle" of close election polls.
Mark Mellman sees significant changes in Barack Obama's base of support, as compared to Kerry in 2004 and Gore in 2000.
Nate Silver sees similar patterns in the Gallup data.
Jennifer Agiesta delves deeper into how increased black turnout might have affected the 2004 outcome.
Allan and Sheri Rivlin think John McCain needs to articulate a credible economic plan.
SurveyUSA rounds up their recent polling on the economy.
The Associated Press has questions and answers for polling skeptics.
Kathy Frankovic says the economic issues remain dominant, as they were in 1992
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