The Day-Of-Week Effect

Pollster.com's Mark Blumenthal writes about another outgrowth of Gallup's daily tracking polls -- Barack Obama tends to do better in surveys that end Saturdays. Hillary Clinton, by contrast, does well earlier in the week, in samples that end Tuesday or Wednesday.

The numbers, first crunched by Harrison Hickman and Ben Margolis, both of the Democratic firm, Global Strategy Group, advise caution as the media marvels in Obama's early-week leads. By the end of the week, Blumenthal notes, the contest should tighten again. Read on.