Get more FiveThirtyEight
- Terms of Use
- Privacy Policy
- Your California Privacy Rights
- Children's Online Privacy Policy
- Interest-Based Ads
© 2018 ABC News Internet Ventures. All rights reserved.
Montana
Likely D
3 in 4
Chance the Democrat wins (76.0%)
1 in 4
Chance the Republican wins (24.0%)
Forecasted turnout
Partisan lean
# What goes into the 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
Lite
D+4.8
Classic
D+4.6
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 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| dates | pollster | sample | weight | Tester | Rosendale | margin | likely voter | Time-line | House effects | Adjusted margin | |
Nov 2-5 11/2-5 | Trafalgar Group | 953 | LV | 1.80 | 50% | 49% | D+1.1 | — | <0.1 |  1.4 | D+2.5 |
Nov 2-4 11/2-4 | Change Research | 879 | LV | 1.69 | 46% | 49% | R+3.0 | — | <0.1 | 0.6 | R+3.6 |
Oct 31-Nov 4 10/31-11/4 | Harris Interactive | 500 | LV | 0.78 | 49% | 43% | D+5.5 | — | <0.1 | 2.3 | D+7.8 |
Oct 30-Nov 3 10/30-11/3 | Harris Interactive | 500 | LV | 0.14 | 49% | 43% | D+6.2 | — | <0.1 | 2.3 | D+8.5 |
Oct 29-Nov 2 10/29-11/2 | Harris Interactive | 500 | LV | 0.12 | 50% | 42% | D+7.6 | — | <0.1 | 2.3 | D+9.9 |
Oct 28-Nov 1 10/28-11/1 | Harris Interactive | 500 | LV | 0.11 | 49% | 42% | D+6.6 | — | <0.1 | 2.3 | D+8.9 |
Oct 27-31 10/27-31 | Harris Interactive | 500 | LV | 0.10 | 49% | 42% | D+6.7 | — | <0.1 | 2.3 | D+9.0 |
Oct 24-30 10/24-30 | Harris Interactive | 700 | LV | 0.24 | 48% | 40% | D+7.7 | — | <0.1 | 2.3 | D+10.0 |
Oct 24-26 10/24-26 | Gravis Marketing | 782 | LV | 0.83 | 48% | 45% | D+3.0 | — | <0.1 | 1.4 | D+4.4 |
Oct 10-18 10/10-18 | University of Montana | 533 | LV | 0.37 | 49% | 39% | D+10.1 | — | <0.1 | 4.9 | D+5.2 |
Oct 8-13 10/8-13 | Montana State University Billings | 471 | LV | 0.37 | 47% | 38% | D+9.0 | — | <0.1 | 0.2 | D+8.8 |
Sep 15-Oct 6 9/15-10/6 | MSU - Bozeman | 2,079 | RV | 0.25 | 46% | 43% | D+3.1 | 0.2 | 0.1 | 2.6 | D+5.5 |
Sep 28 9/28 | Public Policy Polling D | 594 | V | 0.15 | 49% | 45% | D+4.0 | 0.1 | <0.1 | 1.9 | D+2.0 |
Sep 19-22 9/19-22 | Gravis Marketing | 710 | LV | 0.02 | 49% | 45% | D+4.0 | — | 0.1 | 1.4 | D+5.3 |
Sep 17-19 9/17-19 | Axis Research R | 480 | LV | 0.08 | 44% | 44% | EVEN | — | 0.1 | 4.5 | D+4.4 |
Sep 6-16 9/6-16 | Benenson Strategy Group | 950 | LV | 0.10 | 50% | 43% | D+7.0 | — | 0.1 | 0.2 | D+6.6 |
Sep 10-14 9/10-14 | YouGov | 453 | LV | 0.07 | 47% | 45% | D+2.0 | — | 0.1 | 2.3 | D+4.2 |
Aug 13-31 8/13-31 | University of Montana | 466 | LV | 0.00 | 56% | 32% | D+24.0 | — | 0.2 | 4.9 | D+19.2 |
Aug 20-22 8/20-22 | WPA Intelligence R | 600 | LV | 0.02 | 45% | 47% | R+2.0 | — | 0.2 | 6.5 | D+4.7 |
Jul 8-10 7/8-10 | Remington Research Group | 2,581 | LV | 0.00 | 49% | 46% | D+3.0 | — | 0.7 | 4.3 | D+8.0 |
Jun 11-Jul 2 6/11-7/2 | SurveyMonkey | 929 | LV | 0.00 | 54% | 44% | D+10.6 | — | 0.8 | 1.0 | D+12.4 |
Jun 11-13 6/11-13 | Gravis Marketing | 469 | LV | 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. score | Polling avg. | ||
|---|---|---|---|
| Idaho | 56 | — | |
| South Dakota | 53 | — | |
| North Dakota | 52 | R+8.6 | |
| Wyoming | 50 | R+29.6 | |
| Iowa | 50 | — | |
| Missouri | 48 | D+0.5 | |
| Oregon | 45 | — | |
| Nebraska | 43 | R+15.5 | |
| Kentucky | 43 | No race | |
| Kansas | 43 | — |
#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 | |||
|---|---|---|---|
| Expert | rating Rating | Raw | Adjusted |
| Cook Political Report | EVEN | D+0.6 | |
| Inside Elections | D+4.4 | D+5.3 | |
| Sabato's Crystal Ball | D+6.7 | D+6.3 | |
| Average | D+3.7 | D+4.1 | |
How this forecast works
Nate Silver explains the methodology behind our 2018 midterm forecasts. Read more …
Comments