WBUR Senate Poll: Warren Leads Brown By 5

A WBUR poll of 507 likely Massachusetts voters (PDFs — topline, crosstabs) finds Democratic challenger Elizabeth Warren leading Republican incumbent U.S. Sen. Scott Brown, 45 percent to 40 percent. The survey has a 4.4 percent margin of error.

The WBUR poll, conducted Sept. 15-17 by the MassINC Polling Group, is the fourth released this week to find Warren making gains.