Control Variables

In addition to the independent variables of interest discussed in Section 4.3.2, which capture the district-level strength of global city agglomeration processes, I also control for other

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district-level variables that, according to previous IPE scholarship, could be expected to shape mass preferences over globalization, and hence, voting patterns over Brexit. I collected data for these control variables from the most recent UK Census, which provides data at the local authority level.18

First, the Stolper-Samuelson theorem implies that relatively high-skilled districts will favor globalization, since external openness raises the returns to highly-skilled labor in a skill- abundant economy such as the United Kingdom. To account for this mechanism, I use a control variable that measures the percentage of a district’s population that has completed an

undergraduate degree (highereducation). To the extent that skill-based coalitions based on Stolper-Samuelson effects are salient, we should expect to see a positive and significant relationship between highereducation and the district-level share of remain, indicating the presence of a “pro-globalization” coalition of the highly skilled.

Educational levels have traditionally been used to capture Stolper-Samuelson effects in the IPE literature, based on the reasoning that educational attainment represents an investment in human capital that increases an individual’s skill endowment. However, some scholars have pointed out that an undergraduate education not only affects human capital formation, but also affects other factors, unrelated to Stolper-Samuelson effects (such as an intellectual familiarity with comparative advantage) that could also shape foreign economic policy attitudes

(Hainmueller and Hiscox 2006). In light of these criticisms, I also collect Census occupational data that measures the percentage of the district’s population employed as “managers, directors, and senior officials” and in “professional occupations”; for robustness, I use this variable, analogous to measures used to capture Stolper-Samuelson effects in studies of the US congress

18

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(Broz and Hawes 2006; Milner and Tingley 2011) as an alternative (possibly less noisy) measure of skill-based coalitions rooted in the Stolper-Samuelson effect. I label this variable as

professionals.

While the Stolper-Samuelson theorem suggests that highly skilled areas will be more likely to favor globalization (and therefore vote to remain), the Ricardo-Viner approach to foreign economic policy preferences and coalitions puts the analytical microscope on the industrial composition of districts, and expects that districts with high concentrations of

comparative disadvantage industries will be relatively more likely to oppose globalization (and therefore vote to leave). To proxy for the import-competing orientation of districts, I use a measure of the percentage of a district’s population that is employed in the manufacturing sector (manufacturingpercent). This is a relatively coarse measure, since the Census industry-level data is not sufficiently granular to create measures that disaggregate the manufacturing sector into import-competing and export-oriented industries (as is done in studies of American politics). Nevertheless, a recent government study of the UK’s comparative advantage industries noted that as an exporter, the UK “tends to be weak across manufacturing sectors” (Department for Business Innovation and Skills, 22), which suggests that a district’s manufacturing footprint is a good first-cut proxy for the economic importance of comparative disadvantage industries to the local economy. Conversely, it is well-known that the UK has a large comparative advantage in services industries, especially in finance and insurance; to proxy for the export-orientation of districts along Ricardo-Viner lines, I include a variable, labelled FIRE, that measures the district share of the population that is employed in the FIRE (finance, insurance, real estate) industries, in which the UK is internationally competitive.19 To the extent that district-level sectoral

19

Real estate is perhaps note technically tradable, but a measure of finance and insurance employment sans real estate was not available from the Census. In any case, it is well-known that UK property is

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coalitions rooted in Ricardo Viner effects are indeed present, we should expect to see a negative and significant coefficient on the manufacturingpercent variable (since employees of

comparative disadvantage industries are expected to oppose economic openness) and a positive and significant coefficient on FIRE (since employees of comparative advantage industries are expected to favour economic openness).

In addition to these workhorse materialist approaches to explaining foreign economic policy coalitions, more recent work has suggested that deep-seated symbolic and cultural identities acquired early in life (Mansfield and Mutz 2009; Sabet 2014) may be a fundamental driver of attitudes towards globalization. To disentangle the impact of global city agglomeration processes on mass preferences from the impact of pre-existing cultural attitudes—that is, to distinguish the presence of cultural coalitions based on cosmopolitan or ethnocentric attitudes from the presence of spatial coalitions that stem from global city agglomeration processes—it is therefore important to explicitly control for district-level cosmopolitan or ethnocentric identities. Accounting for the impact of cultural preferences on the Brexit vote, and thereby distinguishing cultural coalitions from spatial coalitions, is difficult, particularly at the district-level; it is much more straightforward to account for cultural attitudes at the individual level, which I am able to do in the individual-level analysis carried out in Section 4.4. Here, I attempt to account for the potential impact of cultural values on the vote using two separate measures. First, following previous work that suggests using measures of cultural diversity or multiculturalism to proxy for cosmopolitanism (Warf 2015), I proxy a district’s cultural openness with a variable that

measures the foreign migrant share of the local area population (migrantspercentage). To the

highly sought after across the world, so a measure that includes real estate is perhaps not inappropriate. More generally, the global property market is a central aspect of the global economy, but remains understudied by IPE scholars. It is therefore an important area for future research.

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extent that district-level cosmopolitan or ethnocentric coalitions exerted a meaningful impact on the vote, we would expect to see a positive and significant coefficient on migrantspercentage.

Though the decision to use this proxy to account for the impact of cultural identity on

mass preferences over globalization is grounded in the literature on cosmopolitanism (Warf 2015), it is not without its problems; most importantly, immigration also has labor market effects, and the impact of the district-level share of immigrants on the vote may therefore be a noisy indicator of the presence of cosmopolitan or ethnocentric coalitions grounded in cultural preferences. As an alternative measure, I therefore account for the impact of district-level cultural identity on the vote by controlling for the district-share of individuals with a valid passport; I label this variable passportshare. As Kahler (2017) notes, “transnational experience- literally crossing borders as a result of family background or practices in work or leisure” (7) is linked to cosmopolitan orientations. To the extent that passports are quite literally the keys to transnational experience, they could be a useful proxy for such cosmopolitan cultural attitudes; controlling for district-level passport ownership could therefore help us to distinguish the impact of cultural identity on voting patterns from the impact of global city agglomeration processes (and thereby reassure us that global city and hinterland political coalitions rooted in global city agglomeration processes are empirically distinct from cosmopolitan and ethnocentric political coalitions rooted in the effects of cultural identity).

While political coalitions over globalization organized on the basis of class and skill- levels; industry-level patterns of comparative advantage; and cosmopolitan or ethnocentric identities have been well-studied by IPE scholars, the role of generational or age-based coalitions has received relatively less attention. Though Rogowski (2008) flagged this as a potentially important area of research several years ago, it has not (to my knowledge) become an active area

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of research, and remains under-theorized. However, one of the most striking cleavages that opened up in the Brexit vote was generational, with only 27% of 18-24 year-olds voting to leave the European Union, compared to 60% of those 65 and older (Kelly 2016). Though it is not clear that we yet have a theoretical explanation for this pattern, its empirical importance in the case of Brexit20, as suggested by observational data and the results of previous studies, suggest that it is important to account for such a cohort effect by controlling for the age-composition of districts; this helps to ensure that the observed relationship between our measures of global city

agglomeration processes and patterns of mass support for “remain” does not actually reflect the residual impact of a cohort effect. I account for the age composition of districts with a variable, labelled over65share, which reflects the share of the district population that is over 65 years of age.

Previous empirical studies of Brexit have not emphasized the role of global city agglomeration processes in shaping the Brexit vote. However, as a result of the observed geographic divide between London and the rest of England, these studies have nonetheless attempted to account for the impact of more general spatially defined processes—such as urbanization—on the vote. For instance, some district-level studies, such as Matti and Zhou (2016) use district-level population density to control for the broader effects of urban

20_{Interestingly, an analogous generation gap opened up between Hillary Clinton and Donald Trump in the}

American presidential election, with Hillary Clinton-the internationalist candidate-winning voters in the 18-29 bracket by 18 percentage points. However, a significant age gap featured in the previous two American elections as well (featuring more or less internationalist Republican candidates), so it’s less clear that the generational gap in the US was driven by a populist/internationalist divide. To the extent that it was, though, it’s interesting to note that in the recent French presidential election, Le Pen, the populist candidate, garnered substantial youth support, while Macron, the internationalist, won a sizable share of older French citizens. These cases offer fertile ground for future research on how generational divides and cohort effects might shape the domestic politics of globalization. It could be especially interesting to explore how generational cleavages intersect with other lines of cleavage (for instance, geographic cleavages, or the divide between cosmopolitans and ethno-nationalists).

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agglomeration on the referendum voting patterns. I therefore follow them in including a population density variable in the analysis (labelled popdensity). The inclusion of this variable allows us to distinguish the impact of global city agglomeration processes on the voting patterns from the impact of urban agglomeration effects more generally; to the extent that the coefficients on the globalcity_aggmlomeration and globalcity variables remain positive and significant even after accounting for the impact of the broader phenomenon of urban agglomeration, it would suggest that “global city” and “hinterland” spatial political coalitions over globalization are empirically distinct from, rather than coextensive with, more traditional urban and rural political coalitions. In other words, by including popdensity in the specifications below, we are able to establish that the large-scale spatial political divisions over the Brexit vote (documented in Section 4.2.2) can indeed be traced specifically to the existence of global city and hinterland coalitions underpinned by the economic geography of global cities and hinterlands, and are not simply the byproduct of aggregate patterns of urban agglomeration.

Summary statistics for the independent and dependent variables, are presented in Table 4.2. To assess the extent of collinearity between the measure of district-level global city

agglomeration processes (i.e. the continuous independent variable of interest,

globalcity_agglomeration) and various control variables that attempt to account for other sources

of foreign economic policy coalitions, I also present a table that displays correlations among the various independent variables. This information is contained in Table 4.3.

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Table 4.2: Summary Statistics for District-Level Brexit Analysis

Variable count mean sd min max

percentstay 381 46.88265 10.4119 24.44 78.62 globalcity 381 0.0419948 0.2008409 0 1 highereducation 348 21.38375 6.074746 10.85051 52.71689 professionals 348 13.20761 3.419652 7.26159 31.4726 globalcity_agglomeration 381 0.2624672 0.5299002 0 6.433088 manufacturingpercent 348 4.406307 1.843702 0.8329911 10.88491 migrantpercentage 380 11.17015 3.051181 6.38089 24.78787 over65share 379 19.26816 4.534157 5.991139 32.68029 popdensity 380 584.4593 926.321 2.481847 6007.641 unempincrease 378 0.1357143 0.9984177 -5.2 2.6 FIRE 348 7.336119 3.69288 2.398482 31.8379 passportshare 348 67.21334 3.470896 58.99871 82.82999

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Table 4.3: Correlations Between District Variables in Brexit Analysis

globalcity_agglo meration higheredu cation migrantperc entage over65perc entage manufacturin gpercent professi onals globalcity_agglo meration 1 highereducation 0.3793 1 migrantpercent age 0.3926 0.4943 1 over65percentag e -0.3306 -0.1741 -0.5034 1 manufacturingp ercent -0.2366 -0.5348 -0.4977 0.2776 1 professionals 0.351 0.9437 0.3252 -0.1334 -0.4308 1

It is worthwhile to note that in Table 4.3, the correlations between

globalcity_agglomeration and the variables that capture district-level skill and industry

endowments, are relatively low. These low correlations suggest that the economic geography of global cities and hinterlands, as captured in our measure of the relative strength of global city agglomeration processes (globalcity_agglomeration), is empirically distinct from more traditional vectors of influence on political coalitions such as Stolper-Samuelson or Ricardo Viner dynamics (or for that matter, the effects of cultural identity) and that is not simply a manifestation of processes described or predicted by these traditional models; it is worth noting that these empirical patterns are consistent with certain aspects of the discussion in Section 4.2.3.

This has important implications for our empirical strategy. Recall that this strategy is rooted in the premise that to the extent that our measures of global city agglomeration processes exert a positive and significant impact on district-level “pro-Remain” voting shares after

accounting for alternative determinants of mass preferences over globalization, it points to the existence of independently constituted spatial coalitions rooted in the economic geography of global cities and hinterlands—coalitions which are distinct from coalitions organized on the basis of skill-levels, industrial affiliation, or cultural identity. If the correlations between the measures

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of global city agglomeration processes and some of the other independent variables were especially high—for instance, if districts with high values on globalcity_agglomeration also tended to be highly skilled districts—multi-collinearity may have been an issue. This would have made it difficult to ascertain the independent impact of globalcity_agglomeration on the remain vote, and frustrated our efforts to disentangle spatial coalitions underpinned by the economic geography of global cities and hinterlands from skill-based coalitions based on Stolper-

Samuelson processes. The low correlations between the measures of global city agglomeration processes and control variables suggests that multicollinearity is not likely to be a large concern in the empirical analysis; this makes our strategy for discerning the existence of spatial political coalitions underpinned by the economic geography of global cities and hinterlands a viable one.