by BRENT BENSON
[Note: See this polling average update that includes the last Suffolk University poll.]
City Councilor John Connolly was the early leader in the polling of voters in the head-to-head race for Boston Mayor against State Representative Marty Walsh, but Marty Walsh has surpassed Connolly in the latest UMass poll and a time-weighted average shows a tie with each candidate carrying 42% of the vote.
A graph of the polling numbers with fitted linear regression trend lines shows what seems to be an outlier in Connolly's number of 47% in the UNH poll. A graphical representation of the poll numbers with a regression trend line emphasizes the outlying nature of the point.
Statistical fit measurements confirm that the trend line for Connoly is not very reliable (R-squared of 0.2) compared to the goodness of fit measurements for the Walsh (R-squared of 0.8) and Undecided (R-squared of 0.9) trend lines. While more data would be needed to make a definitive statement, one explanation would be consistent numbers around 40% for Connolly and rising numbers from mid-30s to mid-40s for Walsh.
A look at the gender breakdown in the polls shows Connolly and Walsh approximately tied with men in all but the UNH poll, which has Connolly with a 14 point advantage among males, a number that is way out of line with the other polls. There is a fairly steady trend upwards with women supporters of Walsh.
There is not enough consistency in the polling to declare a strong favorite in the race to replace Mayor Menino. It is clear that Walsh has made headway against the early lead held by Connolly, but it is not clear whether the race is tied, or Walsh has moved into the lead.