Election 2018

Massachusetts

Solid D

>99 in 100

Chance the Democrat wins (99.8%)

<1 in 100

Chance the Republican wins (0.2%)

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Forecasted turnout
Partisan lean

# What goes into the
icon_classic_2
classic forecast in Massachusetts

The Classic version of our model projects a race’s outcome by taking a weighted average of polls of the race (if available), polls of similar races (CANTOR) and non-polling factors (fundamentals). It is then reverted toward a mean based on long-term trends in midterms and presidential approval ratings.

  • D+23.2

    Adjusted polls

  • D+29.0

    CANTOR

  • D+35.5

    Fundamentals

  • D+27.1

    Experts

  • D+23.2

    icon_lite_2

    Lite

  • D+26.1

    icon_classic_2

    Classic

  • D+26.4

    icon_deluxe_2

    Deluxe

  • <0.1

  • <0.1

Historical adjustment

Key

More weight

Less

#Latest polls

We've collected 10 polls for the Massachusetts Senate election. We’re adjusting poll results in three ways: Polls of registered voters or all adults are adjusted to a likely-voter basis; older polls are adjusted based on shifts in the generic congressional ballot since the poll was conducted; and polls are adjusted for house effects (the tendency for a firm’s polls to lean toward Democrats or Republicans). Polls with larger sample sizes and those conducted by higher-quality polling agencies are given more weight, as are more recent polls.

Adjustments
datespollstersampleweight
Warren
Diehl
marginlikely voterTime-lineHouse effects Adjusted margin
Oct 25-28
10/25-28
MassINC Polling Group502LV
1.54
54%32%D+22.0— <0.1 1.4 D+20.6
Oct 24-28
10/24-28
Suffolk University500LV
1.35
56%34%D+21.2— <0.1 0.3 D+20.9
Oct 10-27
10/10-27
Western New England University402LV
0.82
57%27%D+30.0— <0.1 1.0 D+29.0
Oct 1-7
10/1-7
University of Massachusetts Lowell485LV
0.42
56%31%D+25.0— <0.1 0.8 D+25.8
Sep 17-21
9/17-21
MassINC Polling Group506LV
0.04
56%30%D+26.0— 0.1 1.4 D+24.5
Sep 13-17
9/13-17
Suffolk University500LV
0.03
54%24%D+29.4— 0.1 0.3 D+28.9
Jun 8-12
6/8-12
Suffolk University500LV
0.00
55%33%D+22.4— 1.0 0.3 D+23.1
May 22-26
5/22-26
MassINC Polling Group501RV
0.00
54%19%D+35.0 0.2 1.1 1.4 D+34.6
Mar 16-18
3/16-18
MassINC Polling Group504RV
0.00
55%20%D+35.0 0.2 0.9 1.4 D+34.3
Nov 9-12
11/9-12
MassINC Polling Group503RV
0.00
58%32%D+26.0 0.2 0.5 1.4 D+24.0
Weighted averageD+23.2
Partisanship is determined by who sponsors the poll, rather than who conducts it. Polls are considered partisan if they’re conducted on behalf of a candidate, party, campaign committee, or PAC, super PAC, 501(c)(4), 501(c)(5) or 501(c)(6) organization that conducts a large majority of its political activity on behalf of one political party.

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#Similar states and CANTOR

Our state similarity scores are based on demographic, geographic and political characteristics; if two states have a score of 100, it means they are perfectly identical. These scores inform a system we use — CANTOR, or Congressional Algorithm using Neighboring Typologies to Optimize Regression — to infer what polling would say in unpolled or lightly polled states, given what it says in similar states.

Sim. scorePolling avg.
Rhode Island74D+22.2
Connecticut70D+18.8
New Jersey63D+10.1
New York62D+24.7
Maryland50D+33.6
Delaware38D+20.8
Illinois38—
New Hampshire30—
Vermont27D+39.7
Pennsylvania26D+11.7

#Expert ratings

The Deluxe version of our model calculates an implied margin for each race based on expert race ratings from The Cook Political Report, Inside Elections and Sabato's Crystal Ball; it then adjusts that margin toward its estimate of the national political environment.

Equivalent Margin
Expertrating RatingRaw Adjusted
Cook Political Report
Solid D
D+26.7D+27.3
Inside Elections
Solid D
D+26.7D+27.6
Sabato's Crystal Ball
Safe D
D+26.7D+26.3
AverageD+26.7D+27.1

How this forecast works

Nate Silver explains the methodology behind our 2018 midterm forecasts. Read more …

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