Midterm Election Poll: California’s 45th District, Walters vs. Porter (original) (raw)
Katie Porter, the Democratic candidate, has a slight edge in our poll.
Our poll is a decent result for Democrats. But remember: It’s just one poll, and we talked to only 518 people. Each candidate’s total could easily be five points different if we polled everyone in the district. And having a small sample is only one possible source of error.
Where we called:
Each dot shows one of the 32227 calls we made.
Vote choice: Dem. Rep. Don’t know Didn’t answer
To preserve privacy, exact addresses have been concealed. The locations shown here are approximate.
Explore the 2016 election in detail with this interactive map.
About the race
- Katie Porter is a consumer protection lawyer and a professor. 41% favorable rating; 24% unfavorable; 36% don’t know
Based on 518 interviews - Mimi Walters is the current representative and a former investment banker. 40% favorable rating; 42% unfavorable; 18% don’t know
Based on 518 interviews - This often-redrawn district in Orange County, once a pillar of the Reagan-era Republican Party, has experienced an influx of Asian-American and Latino voters. Although some suburban voters may be uneasy with President Trump, the district is not exactly liberal.
- Ms. Walters has supported President Trump on issues like repealing Obamacare and passing a tax overhaul. She says “people are starting to see the benefits of tax reform.” Ms. Porter says the tax law “punishes voters” in this high-tax district compared with people with similar incomes who live in lower-tax states.
- First elected to Congress in 2014, Ms. Walters won re-election handily in 2016 even as Hillary Clinton carried her district.
- Ms. Porter prevailed in a crowded Democratic primary field, running to the left of a more business-oriented opponent. She was backed by Senator Elizabeth Warren and has strongly endorsed single-payer health care.
Other organizations’ ratings:
Previous election results:
| 2016 President | +5 Clinton |
|---|---|
| 2012 President | +12 Romney |
| 2016 House | +17 Rep. |
How our poll result changed
As we reach more people, our poll will become more stable and the margin of sampling error will shrink. The changes in the timeline below reflect that sampling error, not real changes in the race.
One reason we’re doing these surveys live is so you can see the uncertainty for yourself.
If sampling error were the only type of error in a poll, we would expect candidates who trail by five points in a poll of 518 people to win about one out of every eight races. But this probably understates the total error by a factor of two.
Our turnout model
There’s a big question on top of the standard margin of error in a poll: Who is going to vote? It’s a particularly challenging question this year, since special elections have shown Democrats voting in large numbers.
To estimate the likely electorate, we combine what people say about how likely they are to vote with information about how often they have voted in the past. In previous races, this approach has been more accurate than simply taking people at their word. But there are many other ways to do it.
Assumptions about who is going to vote may be particularly important in this race.
Our poll under different turnout scenarios
| Who will vote? | Est. turnout | Our poll result |
|---|---|---|
| The types of people who voted in 2014 | 199k | Walters +2 |
| People who say they are almost certain to vote, and no one else | 210k | Porter +15 |
| Our estimate | 245k | Porter +5 |
| People whose voting history suggests they will vote, regardless of what they say | 249k | Porter +5 |
| People who say they will vote, adjusted for past levels of truthfulness | 259k | Porter +4 |
| The types of people who voted in 2016 | 313k | Porter +3 |
| Every active registered voter | 386k | Porter +6 |
All estimates based on 518 interviews
The types of people we reached
Even if we got turnout exactly right, the margin of error wouldn’t capture all of the error in a poll. The simplest version assumes we have a perfect random sample of the voting population. We do not.
People who respond to surveys are almost always too old, too white, too educated and too politically engaged to accurately represent everyone.
How successful we were in reaching different kinds of voters
| Called | Inter-viewed | Successrate | Ourresponses | Goal | |
|---|---|---|---|---|---|
| 18 to 29 | 3017 | 67 | 1 in 45 | 13% | 12% |
| 30 to 64 | 14972 | 288 | 1 in 52 | 56% | 57% |
| 65 and older | 5783 | 162 | 1 in 36 | 31% | 31% |
| Male | 9679 | 244 | 1 in 40 | 47% | 47% |
| Female | 14115 | 274 | 1 in 52 | 53% | 53% |
| White | 13960 | 326 | 1 in 43 | 63% | 60% |
| Nonwhite | 7784 | 138 | 1 in 56 | 27% | 31% |
| Cell | 15680 | 349 | 1 in 45 | 67% | — |
| Landline | 8114 | 169 | 1 in 48 | 33% | — |
Based on administrative records. Some characteristics are missing or incorrect. Many voters are called multiple times.
Pollsters compensate by giving more weight to respondents from under-represented groups.
Here, we’re weighting by age, party registration, gender, likelihood of voting, race and region, mainly using data from voting records files compiled by L2, a nonpartisan voter file vendor.
But weighting works only if you weight by the right categories and you know what the composition of the electorate will be. In 2016, many pollsters didn’t weight by education and overestimated Hillary Clinton’s standing as a result.
Here are other common ways to weight a poll:
Our poll under different weighting schemes
| Our poll result | |
|---|---|
| Don’t weight by party registration, like most public polls | Porter +6 |
| Our estimate | Porter +5 |
| Don’t weight by education, like many polls in 2016 | Porter +5 |
| Weight using census data instead of voting records, like most public polls | Porter +1 |
All estimates based on 518 interviews
Just because one candidate leads in all of these different weighting scenarios doesn’t mean much by itself. They don’t represent the full range of possible weighting scenarios, let alone the full range of possible election results.
Undecided voters
About 8 percent of voters said that they were undecided or refused to tell us whom they would vote for.
But if they were to break 4 to 1 in favor of Republicans, that alone would be enough to change the lead in our poll, assuming we did everything else perfectly. (We could also be wrong on turnout or our sample could be unrepresentative. Or other voters could change their minds.)
Issues and other questions
We're asking voters about health care, and also whether they support Brett Kavanaugh’s nomination to the United States Supreme Court.
Do you approve or disapprove of the job Donald Trump is doing as president?
| Approve | Disapp. | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 41% | 55% | 4% |
Would you prefer Republicans to retain control of the House of Representatives or would you prefer Democrats to take control?
| Reps. keep House | Dems. take House | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 43% | 51% | 6% |
Do you support or oppose Brett Kavanaugh’s nomination to the United States Supreme Court?
| support | oppose | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 40% | 48% | 12% |
Do you support the creation of a national insurance program, in which every American would get insurance from a single government plan?
| Support | Oppose | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 52% | 41% | 7% |
Do you support repealing and replacing the Affordable Care Act, also known as Obamacare?
| Support | Oppose | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 41% | 55% | 5% |
Do you or a member of your family have a pre-existing health care condition like asthma, heart disease or diabetes?
| Yes | No | Don’t know | |
|---|---|---|---|
| Voters n = 518 | 36% | 62% | 2% |
Percentages are weighted to resemble likely voters.
What different types of voters said
Voters nationwide are deeply divided along demographic lines. Our poll suggests divisions too. But don’t overinterpret these tables. Results among subgroups may not be representative or reliable. Be especially careful with groups with fewer than 100 respondents, shown here in stripes.
Gender
| Dem. | Rep. | Und. | |
|---|---|---|---|
| Female n = 274 / 53% of voters | 52% | 39% | 10% |
| Male 244 / 47% | 45% | 48% | 7% |
Age
| Dem. | Rep. | Und. | |
|---|---|---|---|
| 18 to 29 n = 66 / 13% of voters | 66% | 21% | 14% |
| 30 to 44 83 / 15% | 60% | 35% | 6% |
| 45 to 64 207 / 41% | 46% | 46% | 8% |
| 65 and older 162 / 31% | 39% | 53% | 8% |
Race
| Dem. | Rep. | Und. | |
|---|---|---|---|
| White n = 351 / 66% of voters | 49% | 45% | 5% |
| Black 7 / 1% | 73% | 27% | — |
| Hispanic 65 / 12% | 47% | 41% | 12% |
| Asian 51 / 12% | 51% | 29% | 21% |
| Other 18 / 4% | 46% | 40% | 14% |
Race and education
| Dem. | Rep. | Und. | |
|---|---|---|---|
| Nonwhite n = 141 / 29% of voters | 50% | 35% | 15% |
| White, college grad 225 / 43% | 53% | 42% | 4% |
| White, not college grad 126 / 23% | 42% | 50% | 8% |
Education
| Dem. | Rep. | Und. | |
|---|---|---|---|
| H.S. Grad. or Less n = 26 / 5% of voters | 31% | 63% | 7% |
| Some College Educ. 154 / 28% | 44% | 46% | 10% |
| 4-year College Grad. 167 / 38% | 47% | 43% | 10% |
| Post-grad. 167 / 28% | 58% | 38% | 4% |
Party
| Dem. | Rep. | Und. | |
|---|---|---|---|
| Democrat n = 169 / 32% of voters | 93% | 5% | 3% |
| Republican 172 / 34% | 4% | 87% | 8% |
| Independent 156 / 30% | 55% | 33% | 12% |
| Another party 13 / 2% | 8% | 69% | 23% |
Party registration
| Dem. | Rep. | Und. | |
|---|---|---|---|
| Democratic n = 176 / 33% of voters | 89% | 7% | 4% |
| Republican 208 / 41% | 9% | 85% | 6% |
| Other 134 / 26% | 57% | 26% | 17% |
Intention of voting
| Dem. | Rep. | Und. | |
|---|---|---|---|
| Almost certain n = 334 / 64% of voters | 53% | 41% | 6% |
| Very likely 138 / 28% | 41% | 52% | 7% |
| Somewhat likely 22 / 4% | 34% | 35% | 30% |
| Not very likely 7 / 1% | 13% | 16% | 71% |
| Not at all likely 10 / 1% | 15% | 27% | 59% |
Percentages are weighted to resemble likely voters; the number of respondents in each subgroup is unweighted. Undecided voters includes those who refused to answer.
Other districts where we’ve completed polls
About this poll
- Most responses shown here are delayed about 30 minutes. Some are delayed longer for technical reasons.
- The design effect of this poll is 1.08. That’s a measure of how much weighting we are doing to make our respondents resemble all voters.
- Read more about the methodology for this poll.
- Download the microdata behind this poll.
This survey was conducted by The New York Times Upshot and Siena College.
Data collection by Reconnaissance Market Research, M. Davis and Company, the Institute for Policy and Opinion Research at Roanoke College, the Survey Research Center at the University of Waterloo, the University of North Florida and the Siena College Research Institute.
By Michael Andre, Larry Buchanan, Matthew Bloch, Jeremy Bowers, Nate Cohn, Alastair Coote, Annie Daniel, Richard Harris, Josh Katz, Rebecca Lieberman, Blacki Migliozzi, Paul Murray, Adam Pearce, Kevin Quealy, Eden Weingart and Isaac White