nothing but the truth

From a fascinating WSJ piece about how pollsters are developing strategies to detect and filter out racial and other types of bias in their surveys:

Peter Hart, a Democrat on a bipartisan team conducting the Wall Street Journal/NBC News poll, estimates that 10% of current Democrats and independents who say they support presumed Democratic Party nominee Barack Obama may not be giving a fully honest answer, at least based on their responses to broader questions about race. "This election is exceptionally tricky," he says.

You can take a test for racial bias yourself here.