Data from the Franklin County, Ohio board of elections in Columbus shows how effectively the Obama GOTV effort capitalized on early voting in the blue, urban counties. In Ohio early voting is done both by mail and in person at early voting centers in each of Ohio's 88 counties.
Here's a scatter plot of Franklin County's 802 precincts, with the % of in-person early voting plotted against the Obama support in the precinct:
By the time you get to 90% Obama support (i.e., the predominantly black precincts), 25% of the vote on the average was cast in person at the early voting center on Morse Rd. in Columbus. By contrast the heavily Republican precincts averaged less than 10% turnout at the early voting center.
more...