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Chance the Democrat wins (99.8%)
Chance the Republican wins (0.2%)
We'll be updating our forecasts every time new data is available, every day through Nov. 6.
The Classic version of our model projects a race’s outcome by taking a weighted average of polls of a district (if available), polls of similar districts (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+16.3
Adjusted polls
D+24.3
CANTOR
D+33.3
Fundamentals
D+25.2
Experts
D+17.6
Lite
D+23.7
Classic
D+24.2
Deluxe
<0.1
<0.1
Historical adjustment
Key
More weight
Less
We've collected two polls for Delaware. 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 | Rochester | Walker | margin | likely voter | Time-line | House effects | Adjusted margin | |
Sep. 11-17 9/11-17 | University of Delaware | 728 | LV | 1.14 | 58% | 28% | D+30.0 | — | 0.1 | 10.0 | D+19.9 |
Jul. 24-29 7/24-29 | Gravis Marketing | 884 | LV | 0.53 | 46% | 38% | D+8.0 | — | 0.5 | 1.4 | D+9.9 |
Key
A = adults
RV = Registered voters
V = voters
LV = likely voters
= partisan poll
Our district similarity scores are based on demographic, geographic and political characteristics; if two districts 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 districts, given what it says in similar districts.
Sim. score | Polling avg. | ||
---|---|---|---|
NY-25 | 64 | D+12.8 | |
MD-6 | 63 | — | |
NY-20 | 63 | — | |
PA-7 | 63 | D+7.8 | |
MD-2 | 61 | — | |
MO-5 | 61 | — | |
NJ-1 | 60 | — | |
MA-2 | 59 | — | |
NJ-2 | 58 | D+18.5 | |
NY-24 | 58 | R+13.8 |
The Classic and Deluxe versions of our model use several non-polling factors to forecast the vote share margin in each district.
Factor | Impact | Explanation |
---|---|---|
Incumbency | 3.1 | Lisa Blunt Rochester has been elected to 1 term. Congress has only a 20.1% approval rating, reducing the incumbency advantage. |
District partisanship | 4.8 | Delaware is 13.7 percentage points more Democratic-leaning than the country overall, based on how it has voted in recent presidential and state legislative elections. It voted for Clinton in 2016 and Obama in 2012. Delaware has been considerably more Democratic in state legislative elections than in presidential elections. |
Incumbent's margin in last election | 8.2 | Rochester won by 14.6 percentage points in 2016 in an open-seat race. |
Generic ballot | 6.8 | Democrats lead by an average of 8.6 percentage points in polls of the generic congressional ballot. |
Fundraising | 12.4 | As of Oct. 17, Rochester had raised $374,000 in individual contributions (100% of all such contributions to the major-party candidates); Scott Walker had raised $0 (0%). |
Incumbent's voting record in Congress | 2.6 | Rochester has voted with Democrats 89% of the time in roll-call votes in recent sessions of Congress. Candidates who vote with their party very frequently tend to underperform at the ballot booth, other factors held equal. |
Challenger experience | 0.7 | Walker has never held elected office. |
Scandals | 0.0 | Neither candidate is involved in a scandal. |
Total | D+33.3 |
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 | Raw | Adjusted |
Cook Political Report | D+24.8 | D+25.4 | |
Inside Elections | D+24.8 | D+25.7 | |
Sabato's Crystal Ball | D+24.8 | D+24.4 | |
Average | D+24.8 | D+25.2 |
Nate Silver explains the methodology behind our 2018 midterms forecast. Read more …
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