You could alternatively look at other recent Globe polling:
2013 Senate special election:
Actual June 25: Markey 55 Gomez 45
Globe June 11-14: Markey 54 Gomez 41 - 3-point Dem bias
2010 Gubernatorial election:
Actual Nov. 2: Patrick 48 Baker 42 Cahill 8
Globe Oct. 17-22: Patrick 43 Baker 39 Cahill 8 - 4-point GOP bias, but it should be noted that the Globe never showed Baker leading or a tie
2010 MA-4:
Actual Nov. 2: Frank 54 Bielat 43
Globe Oct. 17-22: Frank 46 Bielat 33 - 2-point Dem bias
2010 MA-10:
Actual Nov. 2: Keating 47 Perry 42
Globe Oct. 17-22: Keating 37 Perry 33 - 1-point Dem bias
2010 Senate special election:
Actual Jan. 19: Brown 52 Coakley 47
Globe Jan. 2-6: Brown 35 Coakley 50 - 20-point(!) Dem bias
You can't really count the last one considering Brown's surge was a last minute event, and Coakley did in fact have a huge lead at that time. As far as MassInc, I can't find any polls they did pre 2012, but they performed much better than the Globe in the only election cycle where they can be compared. Either way, I'm going to believe them considering their polls have been pretty consistent in showing a decent sized Coakley lead whereas the Globe has bounced all over the place this entire cycle for no reason (ex: going from Coakley +7 to Baker +1 in a single week when nothing notable happened in said week).
