By Jim EllisSept. 15, 2018 — Two succeeding polls were just released with one showing Wisconsin Gov. Scott Walker (R) barely leading in his fight for a third term, while another predicts he will be blown out. Yet, the two seemingly contradictory polls both find an almost identical Senate race status.
NBC News/Marist College went into the field during the period of Sept. 30-Oct. 3 (943 Wisconsin adults; 781 registered Wisconsin voters; 571 likely voters) and found Democratic superintendent of public instruction, Tony Evers, leading Gov. Walker by a whopping 53-43 pecent among the likeliest of voters (52-43 percent within the registered voter segment). But, Marquette University Law School, a prolific Wisconsin pollster since the 2012 election cycle, actually finds the governor clinging to a one-point, 47-46 percent edge in their just-released survey (Oct. 3-7; 1,000 registered Wisconsin voters; 799 likely voters).While the two pollsters are far apart in how they see the governor’s race, they are very consistent in projecting the US Senate contest between first-term incumbent Sen. Tammy Baldwin (D) and state Sen. Leah Vukmir (R-Brookfield). NBC/Marist gives Sen. Baldwin a 54-40 percent advantage within their likely voters cell, while Marquette finds a similar 53-42 percent spread.
A simple explanation suggests that the governor’s race is quite volatile while the Senate campaign is virtually decided. The two polls were run consecutively with NBC/Marist ending on Oct. 3 and Marquette beginning on that day. Obviously, this means the Marquette data is the most recent.
The Marquette sampling universe looks to be the stronger, as both the registered and likely voter cells are larger than NBC/Marist’s. Additionally, since Marquette exclusively polls the Wisconsin electorate and does so on what appears to be a quarterly basis but more frequently when closer to an election, their knowledge of the voter base is likely superior to NBC/Marist, which is a national pollster. Therefore, the greater local knowledge likely provides them a superior ability to better pull a reflective sample.