A second poll is showing Republican US Senator Scott Brown leading Democrat Elizabeth Warren by 9 to 10 points, a sign of potential concern for Warren after months of polling showed a closer race.
The poll of 456 voters, conducted by Opinion Dynamics of Cambridge, shows Brown leading Warren 52 percent to 42 percent in a theoretical match-up. Another 1 percent of voters said they were leaning toward Warren.
The poll was conducted for Mass Insight Global Partnerships, a consultant that runs private-public partnerships. Mass Insight released the results to its clients this morning. The poll included a variety of questions for the private use of the firm’s clients, which include universities and businesses.
The Globe obtained the results of a section devoted to political questions. The firm polled a total of 500 residents by phone, but included only 456 registered voters in its results for the political questions.
The poll was conducted between January 31 and Feb. 4, around a period when Brown had a string of legislative victories. It predates the recent controversy over mandatory contraceptive coverage. The poll had a sampling error of plus or minus 4.4 percent.
A second poll conducted by Suffolk University earlier this month showed Brown leading Warren by 9 percent.
Other polls have shown Warren on top.
A WBUR poll released earlier this month showed Warren with a 3-point lead. A University of Massachusetts Lowell/Boston Herald poll in December showed a 7-point lead for Warren.
Mass Insight has been conducting polls for its clients on a quarterly basis since 1989, according to William H. Geunther, the firm’s president. The firm’s October poll showed Brown leading Warren by five percentage points, or 44-39.
The more recent poll also showed Brown remains fairly popular in the state, with 54 percent of respondents saying they view him either strongly favorably or somewhat favorably. Another 38 percent said they view him either strongly or somewhat unfavorably.
Warren, a Harvard law professor and consumer advocate, has never run for public office. The poll showed 22 percent of respondents had never heard of her, compared with 40 percent who had not heard of her in October. Of those who know her, 40 percent said in the most recent poll that they view her favorably, compared with 27 percent who said they view her unfavorably.
The poll also showed former Governor Mitt Romney is unpopular in the state, with 45 percent saying they view him favorably and 52 percent viewing him unfavorably. In a theoretical match-up with President Obama, he would lose 53 percent to 35 percent, according to the poll.