3 in 4

Chance the Democrat wins (76.0%)

1 in 4

Chance the Republican wins (24.0%)

us_map2See the national overview
Forecasted turnout
Partisan lean

# What goes into the
icon_classic_2
classic forecast in Montana

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+3.5

    Adjusted polls

  • D+3.8

    CANTOR

  • D+12.3

    Fundamentals

  • D+4.1

    Experts

  • D+3.5

    icon_lite_2

    Lite

  • D+4.8

    icon_classic_2

    Classic

  • D+4.6

    icon_deluxe_2

    Deluxe

  • <0.1

  • <0.1

Historical adjustment

Key

More weight

Less

#Latest polls

We've collected 22 polls for the Montana 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
Tester
Rosendale
marginlikely voterTime-lineHouse effects Adjusted margin
Nov 2-5
11/2-5
Trafalgar Group953LV
1.80
50%49%D+1.1 <0.1 1.4 D+2.5
Nov 2-4
11/2-4
Change Research879LV
1.69
46%49%R+3.0 <0.1 0.6 R+3.6
Oct 31-Nov 4
10/31-11/4
Harris Interactive500LV
0.78
49%43%D+5.5 <0.1 2.3 D+7.8
Oct 30-Nov 3
10/30-11/3
Harris Interactive500LV
0.14
49%43%D+6.2 <0.1 2.3 D+8.5
Oct 29-Nov 2
10/29-11/2
Harris Interactive500LV
0.12
50%42%D+7.6 <0.1 2.3 D+9.9
Oct 28-Nov 1
10/28-11/1
Harris Interactive500LV
0.11
49%42%D+6.6 <0.1 2.3 D+8.9
Oct 27-31
10/27-31
Harris Interactive500LV
0.10
49%42%D+6.7 <0.1 2.3 D+9.0
Oct 24-30
10/24-30
Harris Interactive700LV
0.24
48%40%D+7.7 <0.1 2.3 D+10.0
Oct 24-26
10/24-26
Gravis Marketing782LV
0.83
48%45%D+3.0 <0.1 1.4 D+4.4
Oct 10-18
10/10-18
University of Montana533LV
0.37
49%39%D+10.1 <0.1 4.9 D+5.2
Oct 8-13
10/8-13
Montana State University Billings471LV
0.37
47%38%D+9.0 <0.1 0.2 D+8.8
Sep 15-Oct 6
9/15-10/6
MSU - Bozeman2,079RV
0.25
46%43%D+3.1 0.2 0.1 2.6 D+5.5
Sep 28
9/28
Public Policy Polling
D
594V
0.15
49%45%D+4.0 0.1 <0.1 1.9 D+2.0
Sep 19-22
9/19-22
Gravis Marketing710LV
0.02
49%45%D+4.0 0.1 1.4 D+5.3
Sep 17-19
9/17-19
Axis Research
R
480LV
0.08
44%44%EVEN 0.1 4.5 D+4.4
Sep 6-16
9/6-16
Benenson Strategy Group950LV
0.10
50%43%D+7.0 0.1 0.2 D+6.6
Sep 10-14
9/10-14
YouGov453LV
0.07
47%45%D+2.0 0.1 2.3 D+4.2
Aug 13-31
8/13-31
University of Montana466LV
0.00
56%32%D+24.0 0.2 4.9 D+19.2
Aug 20-22
8/20-22
WPA Intelligence
R
600LV
0.02
45%47%R+2.0 0.2 6.5 D+4.7
Jul 8-10
7/8-10
Remington Research Group2,581LV
0.00
49%46%D+3.0 0.7 4.3 D+8.0
Jun 11-Jul 2
6/11-7/2
SurveyMonkey929LV
0.00
54%44%D+10.6 0.8 1.0 D+12.4
Jun 11-13
6/11-13
Gravis Marketing469LV
0.00
51%44%D+7.0 0.9 1.4 D+9.3
Weighted averageD+3.5
See more polls

Key

A = adults

RV = Registered voters

V = voters

LV = likely voters

R
D

= partisan poll

Our latest coverage

#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.
Idaho56
South Dakota53
North Dakota52R+8.6
Wyoming50R+29.6
Iowa50
Missouri48D+0.5
Oregon45
Nebraska43R+15.5
Kentucky43No race
Kansas43

#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
Toss-up
EVEND+0.6
Inside Elections
Tilt D
D+4.4D+5.3
Sabato's Crystal Ball
Leans D
D+6.7D+6.3
AverageD+3.7D+4.1

How this forecast works

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

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