This Week's Polls - Which One Is Closer To Correct?

Oct 27, 2016

Credit Matt Bush WCQS

Two polls released this week on the election in North Carolina showed very different results.  The Monmouth University poll released Monday showed Democratic presidential nominee Hillary Clinton and her Republican counterpart Donald Trump in a virtual tie in the hotly contested battleground state of North Carolina.  On Tuesday, a New York Times/Siena poll showed a much different picture.  Clinton led Trump 46% to 39% in that survey.  Each poll also had very different results for the U.S. Senate and governor's elections in North Carolina, with Republicans doing better in the Monmouth poll and Democrats faring better in the NYT/Siena survey.  Each poll was conducted from October 20th to the 23rd, the opening days of early voting in North Carolina.  The Monmouth poll surveyed 402 likely voters, while the NYT/Siena poll questioned 792 likely voters.  

So - which is closer to being correct?

THE RESULTS

                  Monmouth (+/- 4.9%)  NYT/Siena (+/- 3.5%)

President

Hillary Clinton (D)              47%                                  46%                                                

Donald Trump (R)              46%                                  39%

U.S. Senate 

Richard Burr (R)                  49%                                  46%

Deborah Ross (D)                 43%                                  47%

Governor

Pat McCrory (R)                    48%                                 45%

Roy Cooper (D)                      47%                                  51%

DEMOGRAPHICS OF THOSE SURVEYED

We'll compare the demographics of those surveyed in each poll to numbers from North Carolina's Board of Elections and estimates from the U.S. Census Bureau.

Monmouth poll - 30% Democrat - 33% Republican - 37% Independent/3rd party

NYT/Siena poll - 36% Democrat - 26% Republican - 36% Independent/3rd party

Voter registration in North Carolina (from NC BOE as of 10/22/16) - 39.6% Democrat - 30.1% Republican - 30.3% Independent/3rd party

Both polls asked respondents to 'self-identify', meaning they could respond with the party the most align with politically, and not necessarily the party with which they are registered.  That could explain why the numbers don't exactly match up.  With more respondents of the Monmouth poll identifying as Republicans and of the NYT/Siena poll with Democrats, the results of each are reflected.

Monmouth poll - 72% White - 21% Black - 2% Hispanic - 5% other

NYT/Siena poll - 69% White - 20% Black - 5% Hispanic/Latino

Ethnicity of North Carolina (from U.S. Census Bureau estimates 7/1/15) - 63.8% White* - 22.1% Black - 9.1% Hispanic/Latino* - 2.8% Asian - 2.2.% Other

(* - The Census Bureau estimates that 71.2% of North Carolina residents are 'white alone' while 63.8% of residents are 'white alone not Hispanic or Latino'.  That's because the Census Bureau categorizes Hispanics potentially being of any race, and are therefore included in all applicable race categories.)  

Because of how the Census Bureau estimates both white and Hispanic/Latino residents, it's difficult to say whether each poll completely reflects demographics of both.  Both are very near the demographic number of black residents in North Carolina.

Monmouth poll - 46% Male - 54% Female - 52% No college degree - 48% Possess college degree

NYT/Siena poll - 44% Male - 56% Female - 52% Less than college degree - 46% Bachelors degree or higher

Gender and Education Levels in North Carolina (from U.S. Census Bureau estimates 7/1/15) - 51.3% Female - High school graduate or higher - 85.4% - Bachelors degree or higher - 27.8%

The Census Bureau estimates do not include the male population, but based on math it would 48.7% in North Carolina.  The estimates on education level only cover people aged 25 and up, so that does have some effect its accuracy, as there are people younger than that who have completed bachelor's degrees.  Having said that, both polls do rely more on women and those with college degrees than the demographics show.  

CONCLUSIONS

The NYT/Siena poll questioned more people giving it a lower margin of error, while also giving information on where the respondent lived.   The Monmouth poll asked respondents to identify themselves politically (39.6% conservative, 37.3% moderate, 20.4% liberal).  Both had many similarities in terms of ethnicity and gender, but the differences in those who were surveyed were mostly in party identification and political ideology.  And it was reflected in the results of each poll.

So which is closer to correct?  Ask us again November 9th.