Massachusetts votes tomorrow

Tomorrow Massachusetts votes for a new Senator, and it may be a Republican – a scenario almost unthinkable three months ago.

The last four polls have a lead for Scott Brown of 0% (a tie), 5%, 7% and 10%. They were all taken between 15 and 17 January so are recent.

What do the two main polling sites say. Here’s Nate Silver from FiveThirtyEight:

Under its original assumptions, the model now projects a very slight Brown edge, 49.3-48.7, which maps to a 55 percent chance of winning. Earlier today, it had given Coakley a 57 percent chance of winning. However, because the odds are under 60 percent, we still call this race a “toss-up” per our nomenclature, as we did before.

So Brown marginally more likely to win, but too close to call. Further Silver calculates that if you remove a controversial poll that had Brown 15% ahead, then he calculates Coakley has a 68% chance of victory.

At Pollster, Charles Franklin calculates:

But no matter how you slice the data, the only reasonable conclusion is that Scott Brown has moved from well behind to a lead somewhere between 4 and 11 points.