Assessing Recent Partisanship Trends among Millennial Men and Women

Pew Research recently released 2017 data on partisanship among several demographic subgroups that it’s been tracking for decades. Trends in millennial party affiliation by gender–men and women born between 1981 and 1996–have especially gained attention. According to the Pew data, while partisanship among millennial men has been very stable in recent years, millennial women have continuously become more Democratic and less Republican since 2014. Such a trend has very important current and future implications, and so I wanted to check whether other major surveys confirmed this recent change. To do this, I calculated major party identification rates from four other major survey time series during this same time period:

• 2012 and 2016 data from the American National Election Studies
• 2012, 2014, and 2016 data from the General Social Survey
• 2011, 2012, and 2016 from the Voter Study Group (using its cross-sectional and not panel structure here)
• 2011-2016 yearly data from the Cooperative Congressional Election Study.

Below, I show the results along with the data from Pew:

In the context of other survey data, it appears that the recent change among millennial women that Pew shows is a bit more anomalous. ANES data shows millennial women Democratic identification holding steady from 2012 to 2016 (54 and 55 percent, respectively). In the VSG data, Democratic percentage jumps from 52 to 58 from 2011 to 2012, perhaps owing to the Obama re-election year period, but then declines to 51 percent in 2016. CCES data also shows a high point in 2012 (58 percent Democrat, though millennial men also see a high point at that time), but millennial women Democrat identification generally is constant around the 47-49 percent range.

Data from the GSS offers the most support in favor of the Pew time series, as the millennial women Democrat percentage goes from 45 (2012) to 46 (2014) and then to 50 (2016). From 2014 to 2016, Democrat identification also increases among millennial men–though by a smaller amount–so this could just be youth settling into political identities generally (i.e. moving from political indifference to political attachment, a trend that would be expected for all younger Americans).

The VSG data also has a panel structure, where the lack of major movement toward the Democratic Party and away from the Republican Party among millennial women becomes clearer.

The above plot shows the partisanship distribution among millennial men and women by their original (2011) reported partisanship. The specific numbers aren’t important so much as the strong stability at the individual level–around 80-90 percent of partisans among both genders maintain the same affiliation five years later.

In sum, the growth in Democratic attachment and weakening in Republican attachment that the Pew data shows is not really reflected in other time series data from the ANES, VSG, CCES, and GSS to a lesser extent, as well as in the VSG panel data. Instead, a more stable recent picture of partisanship materializes. However, it’s worth noting that the Pew data also includes a 2017 cross-section where millennial women jump another five points in the Democratic direction (70 percent Democrat in 2017) and move away from Republicans by six points (23 percent Republican in 2017). Greater partisan reorientation among millennial women seems to have taken place in 2017 specifically. Unfortunately, none of this other data includes a 2017 cross-section/wave yet for the purposes of comparison. Pre-2017 trends in millennial women partisanship suggest the Pew data represents somewhat more of an outlier, but the 2014-2017 pace of partisanship distribution change in the Pew data is noteworthy, and thus it will be critical to check these other surveys as they release new data.

Update 7/16/18:

I wanted to add two additional notes onto this analysis. First, to establish better comparability between the Pew data (covering registered voters) and other sources, I used only registered voters for the Pew counterpart surveys. For the ANES and CCES, the trajectory of the partisanship gender gap among millennials starts to mirror the increasing one found in the Pew data more closely (see graph here). But the changes still pale in comparison to those from Pew, and notably, the CCES shows millennial men and women both moving in the Democratic direction by similar amounts (unlike what Pew shows).

Second, new data has since come out for the CCES and VSG, making it possible to extend the time series comparison from above to 2017 (where, according to Pew, millennial women further accelerated left). The graph here also incorporates all possible data from before the previously covered time span for the CCES and Pew data. One small change in the arrangement worth noting–instead of a side-by-side within-survey layout used before, the below graph should be viewed from top to bottom (e.g., the first column compares millennial men and millennial women for the CCES).

The trend is still generally unclear, but at least for one of the non-Pew survey datasets (VSG), 2017 does usher in some of the growing women millennial split found in the Pew data. Specifically, in the VSG, millennial women move two points more Democratic and four points less Republican from 2016 to 2017, while for men the changes are two points less in both the Democratic and Republican directions. Of course, the Pew trend exceeds the VSG one, as Pew shows women moving five points more Democratic and six points less Republican. Checking for only (self-reported) registered VSG voters doesn’t make the trend there match the Pew one any more closely. The CCES, on the other hand, does not show an increase in millennial women Democratic identification (though they do move five points less Republican in this data). Incorporating other 2017 data points thus seems to add some confirmation to the Pew pattern in gendered millennial partisanship trends, but Pew remains slightly more of an outlier in this respect.

Black Attachment to the Democratic Party and Co-Racial Context

I recently read a great working paper titled “Bound by Blackness: Understanding the Maintenance of Black Democratic Party Loyalty” by Laird et al. that sheds important new light on the partisanship of African-Americans. The persistently strong attachment to the Democratic Party among blacks has long been explained as a function of “linked fate” (concern among blacks with what happens to blacks as a group). However, after showing the weak evidence for this theory, these authors use several pieces of evidence to argue for a different theory that center on social sanctions leading blacks to overwhelmingly identify as Democrat. Namely, pressure from group expectations leads to greater compliance with the group norm that is Democratic support among blacks. Some of these same authors offer compelling evidence for this same theory in other research as well.

I thought one natural (and simple) extension of this work would be to check how black political identity varies by local social context. With its large sample of blacks (7,920) and geographic codes (county FIPS and zip code) that could link to social context demographic data from the Census, the 2016 CCES provides a good opportunity to see whether black political identity varies by the extent to which they live near other blacks. In this way, while far from perfect, I could capture a similar mechanism of pressure to comply with group norms driven by the amount of surrounding group members who could influence an individual. My general expectation is thus that blacks should have greater attachment to the Democratic Party in areas that contain more blacks.

In the above plot, I generally find support for this expectation. The x-axis shows 10 intervals representing the percentage of blacks living in black survey respondents’ zip codes, and the y-axis shows the percentage of black survey respondents that identify as Democrat (Democrats + Democrat leaners). In zip codes that range from 0 to 10 percent black, blacks identify as Democrat 74.1 percent of the time. At the highest level of living with co-racial individuals–in the 90-100 percent black zip code range–blacks identify as Democrat at a 89.8 percent rate. Thus, if the social sanctions theory applies here, blacks receive the least amount of group pressure to comply with norms (i.e. Democrat support) in the areas with least amount of fellows blacks (0-10 percent) and that translates into the lowest level of Democratic attachment across all zip code ranges. In a local context where blacks live with many other blacks (90-100 percent), blacks identify as Democrat at the highest rate across all zip code ranges, perhaps because of greater pressure to comply with group norms as part of living around more co-racial individuals. (Note: the proportions at 90-100 and 80-90 are statistically significantly different at conventional levels, but the 90-100 and 30-40 proportions are only different at p<0.10.)

Interestingly, black Democratic attachment does not monotonically increase as percentage black zip code increases. Instead, there’s a peak at the 30-40 percentage range, after which Democratic attachment decreases and then picks up again around the 80-90 and then 90-100 range. The relationship therefore doesn’t perfectly follow my expectation, and so the evidence here is not extremely strong. However, the Democratic identification estimates at the highest and lowest levels of black zip code percentage ranges is telling, and suggest there is some type of context effect that shapes the extent to which blacks support the Democratic Party. In this sense, the results here lend some additional support for the theory of social sanctions and group compliance pressures as an explanation for black partisan homogeneity.

Update 3/22/18:

I plotted the same relationship from the last graph but broke it up by self-described (five-point) ideology below. Interestingly, the relationship between amount of co-racial individuals and attachment to the Democratic Party appears stronger among the two conservative groups (“conservative” and “very conservative”) than among the other ideological groups. As with the overall relationship, this specific result mirrors another one of the findings from Laird et al.’s work: conservative blacks experience this social pressure to conform to group expectations (based on their social context) the most.