Which Countries Are the Most Divided?

By Matthew Gentzkow

Posted on November 5, 2021


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There are many ways to measure political polarization among voters. We can look at peoples’ views on policy issues like taxes and immigration, or the intensity of their self-declared ideologies and partisan affiliations. We can look at how consistently they vote for one party or another. Many of these measures show trends toward increasing polarization in the US in recent decades.

 

For the clearest picture of America’s deepening political divides, however, it helps to look not at traditional political choices but rather at measures of how people feel about those in the opposite party. Affective polarization is a standard measure of these feelings, defined as the extent to which people report feeling more negatively toward the opposite political party than to their own. It was popularized as a polarization measure by Shanto Iyengar and co-authors.(1)

 

Us and Them

 

Affective polarization has risen substantially in the US in recent decades. In 1978, the average partisan rated in-party members 27.4 points higher than out-party members on a “feeling thermometer” ranging from 0 to 100. In 2020, the difference was 56.3 points. Scholars have argued that growing affective polarization may have important consequences, including a reduction in the efficacy of government, increasing the self-segregation of social groups, and altering economic decisions.

 

“Among the 12 OECD countries for which we were able to get data, the US has the largest increase in polarization. After 2000, all countries except Britain and Germany exhibit a positive linear trend.”

 

In a recent paper(2), we examine whether affective polarization has seen similar increases in other developed democracies over the past four decades. This kind of comparative evidence remains rare. It is interesting not only for its own sake but also because it tells us something about the likely drivers of polarization. In particular, if rising polarization is the result of factors like the growth of the internet and social media, globalization, and growing inequality, which have been present in all such countries, we might expect rising polarization to be relatively universal. We show that this is not the case.

 

“Among the 12 OECD countries for which we were able to get data, the US has the largest increase in polarization. After 2000, all countries except Britain and Germany exhibit a positive linear trend.” …12 OECD countries for which we were able to get data for the past four decades, the US stands out with the largest increase in polarization. In five other countries — France, Denmark, Canada, New Zealand, and Switzerland — polarization also rose, but to a lesser extent. In the remaining six countries — Japan, Australia, Britain, Norway, Sweden, and (West) Germany — polarization fell. Focusing on the period after 2000, all countries except Britain and Germany exhibit a positive linear trend, with the US having the largest estimated trend among all sample countries. Overall, these results suggest rising polarization may be driven by factors that are more distinctive to the US.

 

One important point to note is that a flat or declining trend over the 40 years of our sample does not rule out the possibility that countries have seen rising polarization in the most recent years. Britain, for example, shows a slight overall decline but a clear increasing trend post-2000 (and post-Brexit).

Figure 1, titled " Trends in affective polarization by country", shows trends in affective polarization for the 12 countries in the sample study. There is a strong rising trend in the US; smaller positive trends in France, Denmark, Canada, Switzerland, and New Zealand; and declines in Japan, Australia, Britain, Norway, Sweden, and Germany.

Figure 1: Trends in affective polarization by country

Measuring the Divide

 

To conduct our analysis, we constructed a new database from 149 different surveys, many of which had to be harmonized manually. These data permit a first look at long-term cross-country trends in affective polarization, but they also have important limitations. Question wording and response scales — as well as the set of years with available survey data — differ across countries and, in some cases, across survey years for a given country. Because the number and nature of political parties differ across countries and within countries over time, even identically structured survey questions may take on different meanings in different contexts. We analyze the sensitivity of our findings to restricting attention to the top two parties in each country and focusing on periods in which this pair of parties is stable.

 

“One explanatory factor is increasing racial diversity. The non-white share of the population has risen sharply in the US; and in New Zealand and Canada, where we see rising polarization as well.”

 

From each survey, we extract each respondent’s party identification as well as a measure of each respondent’s affect towards the parties in their country. Questions about affect vary across surveys, commonly asking respondents how they feel towards a given party, how much they like the party, or to what extent they sympathize with the party. We transform the responses in each survey so that the minimum response is 0 and the maximum response is 100. We refer to the transformed response as the respondent’s reported affect towards the given party.

 

We then define our main measure of polarization to be the difference between average affect toward one’s own party and average affect toward all other parties, weighted by their shares in the population.

 

American Exceptionalism

 

In the final part of the paper, we consider potential explanations for rising polarization. We look at the correlation between trends in affective polarization and trends in possible drivers. This analysis cannot conclusively establish what causes polarization, but it can suggest explanations that would be most promising to explore further.

 

The data do not provide much support for the hypothesis that digital technology is the central driver of affective polarization. The internet has diffused widely in all the countries we look at, and under simple stories where this is the key driver we would have expected polarization to have risen everywhere as well. In our data, neither diffusion of internet nor penetration of digital news are significantly correlated with increasing polarization. Similarly, we find little association with changes in inequality or trade.

 

One explanatory factor that looks more promising is increasing racial diversity. The non-white share of the population has increased faster in the US than in almost any other country in our sample, and other countries like New Zealand and Canada where it has risen sharply have seen rising polarization as well.

 

Another potential driver is the nature of the divisions between political parties. The period we study saw important changes in the composition of the parties in the US. Among both political elites and voters, party identification became increasingly aligned with both political ideology and social identities such as race and religion. This was due in part to the political realignment of the South, where conservative whites shifted from the Democratic to the Republican party. The period also saw sharp increases in the polarization of party elites in the US as measured by roll-call voting. Increases in the sorting of parties to ideologies and polarization of elites are associated with rising polarization in our data, the second significantly so.

 

Key Takeaways

 
  • There is a strong rising trend of affective polarization in the US; smaller positive trends in France, Denmark, Canada, Switzerland, and New Zealand; and declines in Japan, Australia, Britain, Norway, Sweden, and Germany.
     
  • The evidence does not support simple stories in which digitalization, inequality, and globalization are the main drivers of polarization.
     
  • Rising polarization appears more likely to be a result of factors that vary across countries, such as changing party coalitions and racial divisions.
     

References:

  1. See Shanto Iyengar, Gaurav Sood, and Yphtach Lelkes, 2012, “Affect, not ideology: A social identity perspective on polarization,” Public Opinion Quarterly, 76(3): 405–431.
     

  2. This article for TNIT News draws on material from Levi Boxell, Matthew Gentzkow and Jesse M. Shapiro, 2021: “Cross-Country Trends in Affective Polarization”, Stanford University working paper
     

The preceding is republished on TAP with permission by its author, Professor Matthew Gentzkow, and by the Toulouse Network for Information Technology (TNIT). “Which Countries Are the Most Divided?” was originally published in TNIT’s September 2021 newsletter.

 

Note: a previous version of this article was published on TAP in January 2021 as “Cross-Country Trends in Affective Polarization”.


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