Question
If the November 6 election for the US Senate were being held today, would you vote for Dianne Feinstein, a Democrat, or Kevin de León, a Democrat?

About this Poll
Findings in this report are based on a survey of 1,711 California adult residents, including 1,198 interviewed on cell phones and 513 interviewed on landline telephones. Interviews took an average of 19 minutes to complete. Interviewing took place on weekend days and weekday nights from July 8–17, 2018.

Cell phone interviews were conducted using a computer-generated random sample of cell phone numbers. All cell phone numbers with California area codes were eligible for selection. Once a cell phone user was reached, it was verified that this person was age 18 or older, a resident of California, and in a safe place to continue the survey (e.g., not driving). Cell phone respondents were offered a small reimbursement to help defray the cost of the call. Cell phone interviews were conducted with adults who have cell phone service only and with those who have both cell phone and landline service in the household.

Landline interviews were conducted using a computer-generated random sample of telephone numbers that ensured that both listed and unlisted numbers were called. All landline telephone exchanges in California were eligible for selection. Once a household was reached, an adult respondent (age 18 or older) was randomly chosen for interviewing using the “last birthday method” to avoid biases in age and gender.

The sampling error, taking design effects from weighting into consideration, is ±3.4 percent at the 95 percent confidence level for the total unweighted sample of 1,711 adults. This means that 95 times out of 100, the results will be within 3.4 percentage points of what they would be if all adults in California were interviewed. The sampling error for unweighted subgroups is larger: for the 1,420 registered voters, the sampling error is ±3.6 percent; for the 1,020 likely voters, it is ±4.3 percent. Sampling error is only one type of error to which surveys are subject. Results may also be affected by factors such as question wording, question order, and survey timing.