Brown a 74% Favorite in Mass. Senate Race

Scott Brown is now a 3:1 favorite to win today’s Senate race in Massachusetts, according to FiveThirtyEight.com’s much-vaunted forecasting model. A host of recent polls give Coakley steadily worsening numbers, so the site, which correctly predicted all 35 Senate races in 2008, rates the race as “Lean GOP.” But Nate Silver warns that there’s “a higher-than-usual chance of large, correlated errors in the polling.”

Silver notes, for example, that pollsters are more error-prone in special elections, and that his model itself may be too slow for the Massachusetts race. “Voters and political operatives should continue to proceed as though every vote matters,” he cautions, "so we are still well within the range where small, decimal-point shifts in turnout could have a comparatively large impact.” (More Nate Silver stories.)