Recent Panel Evidence on the Level of Over Time Public Opinion Stability

A long-debated question in political science is how coherent public opinion is among the masses. In particular, a seminal finding in this line of study holds that people are very unstable in their policy opinion over time–expressed opinions at one point often change when probed years later. Panel data from the Voter Study Group contains several of the same opinion questions asked in 2011 and 2016 of the same 8,000 people, and thus offers some more recent evidence for answering the question of over time opinion constraint. I take a look at nine of these VSG questions in the graphs below, spanning a wide range of issue areas. All of these have different response scales (some range from 1-5, others just provide just two options and thus range from 0-1). In Figure 1, I calculate the point change on each survey question scale from 2011 to 2016, and then graph the survey respondent distribution for this opinion change indicator (a value of zero indicates no opinion change, while each value greater than that means greater opinion shift).

Figure 1

Interestingly, considerable over time opinion stability emerges. On survey questions that include only two responses, people maintain the same opinion five years later at very high rates (between 82 and 90 percent, with a high of 90 for opinion on the legality of gay/lesbian marriage). On questions with three survey scale points, the percentage exhibiting no opinion change ranges from 73 to 79 percent. More change appears for the four-question racial resentment battery–which makes sense given evidence of racial attitude change over the last decade or so–but even here almost all of the movement is between 0 and 1 point changes on a 1-4 point scale. The greatest opinion change forms for the question of whether it should be made harder or easier for foreigners to immigrate to the U.S. (a majority move at least one point). But again, much of that shift is confined to one-point movement on the scale (35 percent) amid a plurality who see no change (45 percent).

Another way of assessing over time opinion stability has used correlation coefficients (such as in Converse 1964).  Table 1 shows the correlation for each item between measurements in 2011 and 2016. Most of these reveal very strong correlations, and thus further reinforces a picture of stable over time public opinion from 2011 to 2016.

Table 1

Of course, it’s worth keeping in mind some caveats for this evidence of high over time opinion constraint. First, as with all panels, the VSG is likely made up of an especially politically sophisticated sample (staying on the panel and completing a second wave five years later) and thus this might not represent the broader American population too well. Second, the issues that appear in both waves seem to cover more entrenched attitudes–in terms of saliency in the public discourse (abortion, global warming, healthcare) and less policy-based and more group-centered beliefs (anti-black racial resentment and immigrants). In this sense, answers to these questions might not be representative of all public opinion attitudes.

Reviewing Data on the Individual Level Stability of Partisanship Entering the Trump Era

Recently, there’s been renewed interest in the question of how stable partisan identification is, especially with respect to what it means for Donald Trump’s approval rating numbers. Some have questioned the common belief of partisanship’s fixed nature, motivated by potential change introduced by the Trump presidency. This prompts the question of what evidence exists that can shed light on whether the Trump era has ushered in substantial party identification change at the individual level. I’ll quickly summarize relevant data here, focusing on available panel datasets that include a wave before (or at least in the early parts of) the Trump era and another wave sometime during the Trump era (around the 2016 election or after).

1. Voter Study Group, wave 1 in December 2011 and wave 2 in July 2017: VSG 2011-2017: 86 percent of 2011 Democrats and 87 percent of 2011 Republicans maintain the same partisan affiliation six years later, while the D->R conversion rate is 6 percent (among 2011 Democrats) and the R->D rate is 3 percent (among 2011 Republicans)
2. Pew Research Center, wave 1 in December 2015 and wave 2 in March 2017: 88 percent of 2015 Democrats and 87 percent of 2015 Republicans stay constant in their partisanship two years later; the D->R shift is 10% and R->D is 11%, though greater some turnover occurs in the intervening time period
3. GfK Ltd., wave 1 in October 2012 and wave 2 in October 2016 (from Mutz 2018 who made data public): 94 percent of 2012 Democrats and 96 percent of 2012 Republicans maintain the same partisanship four years later; D->R rate is 5 percent and R->D is 3 percent (one note: the public dataset didn’t include weights, so these are unweighted percentages)
4. CBS/YouGov: waves in January 2017 and July 2017 show 92 percent of Democrats and 90 percent of Republicans stay constant in party identification, while the D->R rate is two percent and the R->D rate is three percent; strong partisanship stability and low switching rates also appear in comparing waves from February/March 2017 and May/June 2018
5. YouGov 2015-November 2017 (from Bartels 2018): although partisan consistency rates are not reported, party switching is again very low as only four percent of 2015 Democrats become Republican in 2017 and five percent of 2015 Republicans become Democrats in 2017

In sum, across several sources of survey data and survey modes (though three out of the five are YouGov-based), the evidence points to individual level partisanship being very stable and altered very little in the era of Trump presidency. Moreover, the direction of the little partisanship change that has occurred is inconsistent across survey source (in some cases the D->R shift is larger, in others it’s the opposite). A next step might be to historically contextualize these rates of partisan stability and change around the time of presidency transitions with previous ones, and thus get a better sense of what this recent change means. Compared to the period before Trump entered the political scene, for example, the rates of partisan constancy and change as of late look even less exceptional. Namely, in the 2010-2014 CCES panel dataset, 92 percent of Democrats and 90 percent of Republicans stuck with the same partisan affiliations over the course of four years (D->R was two percent and R->D was three percent).

Have Women Shifted Democratic during the Trump Era? (Data for Progress)

I recently wrote a post for the Data for Progress blog about historical and recent patterns in the gender gap–with special attention to whether or not women have become more Democratic as of late–across three areas: partisanship, general election vote choice, and midterm election vote choice. You can check out the post here and some of the graphs used in the piece below.

Gauging the Level of Over Time Issue Polarization among Partisans

The question of the extent and nature of polarization in the American public has received much attention from political science. Though not always debated on this front, polarization on issue and policy opinion is a nuanced subject and sometimes suffers from limitations from survey data. For example, survey questions on policy issues often offer binary responses, which can measure what side individuals fall on but not the extremity of their positions. Furthermore, most data sources on mass issue opinion lack the ability to give a historical account of polarization, as they simply have not been asking questions long enough. The American National Election Studies does not suffer from these pitfalls as much, however, having asked many of the same issue and ideological questions across several decades and doing so with survey scales that capture position extremity. As a result, analyzing the ANES can produce a uniquely informative picture of over time polarization on issue/policy opinion–namely, speaking to how divided Democrats and Republicans have become in their opinion across various issue domains.

That’s what the below graph illustrates–the average position of both major partisan group for nine issue/ideological time series questions asked in each ANES survey over the past few decades. Some of these questions fall on four- or seven-point scales in their original form, so to make them comparable, I code each to run on a 0 to 1 scale where 0 marks the most liberal position on the question and 1 represents the most conservative position.

From a qualitative perspective, these average partisan positions on several issues suggest not much ideological polarization has developed over the last few decades. Partisan gaps certainly stay constant throughout the years on every issue and some issues do see growing differences (e.g. abortion rights opinion comes closest to movement to the ideological “poles”). But for the most part, Democrats and Republicans appear to (1) not be substantially divided on the issues and (2) their divisions do not appear to be growing too heavily. Instead, year-to-year changes in opinion across both partisan groups seemingly track one another, offering support for a “parallel updating” account. For example, over time correlation coefficients between each partisan group’s position are mostly positive (for seven of nine positions) and moderate to strong in size (0.10, 0.26, 0.29, 0.30, 0.48, 0.90, 0.91 for the seven).

On the other hand, plotting the yearly differences between Democrats and Republicans on each position from above makes it makes it clear that for most areas, partisans are moving further away from each other on the issues over time. The below graph depicts these gaps and corroborates this trend of growing divisions.

This graph puts a “magnifying glass” to the differences, so it’s worth keeping in mind the y-axis scale being used and how that accentuates these gaps. The growing differences are still not too sizable by any means–and not to the extent of considerable polarization in issue opinion that many often assume defines American politics. Nevertheless, divisions on the issues indeed have grown over the last few decades and up through the last election year, occurring most acutely for abortion rights, government aid to blacks, and self-described ideology.

Many might interpret these growing opinion divisions among the partisan masses as a response to growing polarization among party elites. In this sense, we might expect partisans who are most politically aware and attentive to elite discourse to receive elite cues about changing issue positions the most and change their opinion in ideologically consistent directions to a greater degree. The below graph plots the same average partisan position difference from above in green and the difference for only the most politically knowledgeable individuals in orange. Correct answers to a question about what party has a House majority–which, importantly, is a political knowledge question common to all the survey years of interest–distinguishes high knowledge respondents.

Comparing average partisan distance for all respondents versus just high knowledge ones confirms the expected pattern: high knowledge partisans–those likely most receptive to elite cues on policy issues–lead the way on driving ideological polarization. The orange line representing them for the most part lies above the green line (all people) across most years and issues, demonstrating greater issue opinion difference exists (which the y-axis measures) for this group. While there isn’t a good comparison for this dynamic, it is interesting that these differences between high knowledge and all individuals are not that large–absent for some issues and muted in others.