Why and how do think tanks expand their networks in times of crisis? The case of Bruegel and the Centre for European Policy Studies

ABSTRACT The eurozone crisis has spectacularly increased the European Union’s (EU’s) institutional demand for expert knowledge. While the crisis has challenged the legitimacy of the EU in many ways, it has in contrast amplified the visibility and the role of Brussels-based think tanks as laboratories of ideas that think ahead about eurozone governance and policies. Drawing on the analysis of more than 450 expert reports produced by two leading Brussels-based think tanks, over 300 CVs and biographical notes as well interviews, this article explores when, how and why Brussels-based think tanks expand their networks in times of crisis. While the article leaves aside the question of their ideational impact upon agenda-setting and the policy formulation process leading to the new European economic governance, it shows how think tanks adapt to crises and how they seek to have a voice in thinking about the future of the EU’s economic governance.


Introduction
As the global 2008 financial crisis has brought to the fore the limitations of neoliberal economic policy, new questions have been put at the centre of research puzzles to understand the resilience of neoliberalism (Plehwe 2011). Both in the United States and in Europe, economists have tended to fulfil roles as 'popular experts and prophets' (Campbell-Verduyn 2016: 519), in a context of strong doubts about the irrefutable character of economic laws (Jorion and Colmant 2014). Exploring the fields of power, academics have explained why austerity policies prevailed in expert and political milieus while popular dissent was mounting (Campbell and Pedersen 2014;Georgakakis and Rowell 2013;Helgadóttir 2016;Lebaron 2012;Seabrooke and Tsingou 2014). These contributions go beyond the postulate according to which economic ideas matter. What this emerging body of research convincingly demonstrates is how certain economic ideas penetrate the fields of power in European Union (EU) and global governance (Ban 2015; Carstensen and Schmidt 2016;Lebaron 2012;Mudge and Vauchez 2015). While the contribution of American economists and experts to the recent financial and economic crisis has been scrutinised in a set of academic articles, little is known about the role of their European counterparts based in Brussels. This article is a contribution to this debate.
At the beginning of the eurozone crisis, the political demand for expert economic knowledge increased at the EU level. Recognising high policy uncertainty, EU institutional actors closed ranks and struggled to find solutions to calm the markets, to secure the euro and to prevent disintegration (Schmidt 2016). They sought to legitimize their decisions through expert knowledge, regardless of the unpopularity of technocratic means and solutions. They did not seek to find out what their constituencies want; they rather sought to identify what markets wanted and how to legitimize unpopular decisions, that is to reduce public spending and to ensure fiscal and budgetary discipline. In doing so, they strengthened their ties with think tanks, academics and experts of all persuasions. While EU institutional actors closed ranks in the first years of the crisis, in contrast Brussels-based think tanks enlarged their networks, involving in the production of their analyses more experts than ever before. The number of reports providing policy solutions spectacularly increased to attain its highest point in 2011 in 2012. The question is: why do Brussels-based think tanks expand their networks? How does it happen? Put differently, what do crises do to this kind of organization?
I argue that the eurozone crisis has been an opportunity for Brussels-based think tanks rather than a constraint. In the first years of the crisis (2010)(2011)(2012)(2013) research became the new word in town. The crisis gave them more weight in their relations with EU and global decision-makers. In just a couple of years, the two leading Brussels-based think tanksthe Brussels European and Global Economic Laboratory (Bruegel) and the Centre for European Policy Studies (CEPS)have managed to increase their budgets (although through different means) and to strategically expand their networks. The enlargement of the networks has been driven by three considerations: differentiation; credibility; and reputation. Bruegel has sought to connect the United States in debating problems of global and European economy, while research production by the CEPS has reflected more the continental economic philosophy, with a focus on the German and French traditions and connections in the EU-28. While Bruegel's ecology has brought together economists with experience in national banks, the International Monetary Fund (IMF) and the World Bank (WB), those involved in expert knowledge production at the CEPS have acquired their professional experience in EU member states, national research centres and think tanks.
The article draws on 461 published reports produced by Bruegel and the CEPS dealing with the eurozone crisis from 2008 to 2016. From these reports, I retrieved the names of their authors. Drawing on the full CVs and detailed biographical notes, 1 I examined their professional paths and their ties with European/international/national institutions. To understand the strategy of Bruegel and the CEPS, I conducted interviews with two renowned senior economic researchers from the think tanks under consideration.
In what follows, the next section introduces the research puzzle and puts forward the theoretical argument. Next I depict the place of Bruegel and the CEPS in the market of ideas in Brussels. Then I show when, how and why Brussels-based think tanks expand their networks in times of crisis.

Theorizing think tanks' behaviour in time of crisis
The eurozone crisis shifted the locus of power in EU decision-making. I argue in this article that, while it has altered the EU's modes of governance and domestic policies, it has also challenged Brussels-based think tanks in many ways. As Stone and Ladi put it, in recent years, 'an increasingly important locus of policy power, decision-making and implementing authorities operates above and beyond the state and is executed by transnational policy actors ' (2015: 840). Neither international financial organizations, nor EU institutional actors are the determinants of global/European policies (Stone and Ladi 2015: 843). Since the beginning of the crisis, new actors have been empowered and more hybrid policy areas have emerged. In economic governance, as in many other issues, 'transnational policy communities exercise growing power and authority over cross national problems' (Stone and Ladi 2015: 844). These are not 'neatly bounded and nested spaces' (Stone and Ladi 2015: 842). In these loci of powers, a wide range of actors interact through formal and informal means of governance. Among them think tanks and scientific and expert groups use their savoir and transform it into usable knowledge to shape global/European policy agendas. Put differently, they use intellectual arguments to legitimize policies and power relations. They are tied together in complex patterns of interactions that this article seeks to reveal. Against this backdrop, this article seeks to theorize about the behaviour of leading Brussels-based think tanks since the fast-burning phase of the eurozone crisis (2010-2012) onwards to see how they have conceived their roles and how they have sought to adapt their functions.
Expert knowledge has always played a role in EU policy-making. EU institutions, like their national counterparts, are dependent on expertise in different ways. At the European level, as in any advanced democracy, 'politicians want a justification for pre-existing political programs' (Haas 2004: 571). To this end, they have constantly encouraged civil society participation to lend authority to certain policy decisions (Boswell 2008: 473). As the EU has matured, evolving towards a complex political system covering a wide range of policies, the number of interest representationseconomic actors, trade unions, regions, private companies, think tanks etc.has been growing steadily since the 1980s onwards. The deepening of the integration process has triggered 'an increasing need for specialist knowledge, new ideas and policy alternatives' (Ullrich 2004: 52).
European and national think tanks act as bridges between professionals/ academics and states and international organizations (Boucher et al. [2004]; Sherrington [2000]; Stone [2000Stone [ , 2007; Ullrich [2004]). Their aim is to disseminate policy solutions to inform/influence the decision-making process. They are 'scientific establishments, composed of experts and scholars engaged in the task of thinking, writing and publishing' (Stone 2007: 261). Most of those established in Brussels were created with the aim to bring citizens closer to the EU, to shape decision-making and, by the same token, to reduce the democratic deficit. The most ambitious think tanks have sought to generate 'big and small ideas at the EU level', to evaluate public policies, and to provide specific expertise to political actors and competing visions on European integration (Sherrington 2000: 178, 182).
However, back in 2004, in the context of vivid debates about the non-respect of the conditions of the Stability and Growth Pact (SGP) by France and Germany, a report produced on behalf of Notre Europe, the Paris-based think tank, concluded that EU decision-makers perceived the dozens of Brusselsbased think tanks by as being 'useful' but with 'limited added value for the decision-making process' (Boucher et al. 2004: 87). EU institutional actors deplored the inability of European think tanks to offer 'truly innovative ideas' for the decision-making process (Boucher et al. 2004: 87). The picture was looking bleak in the eyes of observers and decision-makers, who lamented that Brussels-based think tanks 'lack creativity', 'feed an elite' and fail in bringing the EU closer to its citizens (Boucher et al. 2004: 87). Prior to the crisis, observers argued that think tanks in Brussels tended to be 'rather mainstream' and traditional supporters of EU integration (Missiroli and Ioannides 2012: 7).
Nonetheless, at the beginning of the eurozone crisis in 2010, EU institutional actors and international organizations such as the IMF and the WB commissioned research, while at the same time they sought to strengthen their internal research units and departments (Ban 2015; Mudge and Vauchez 2015;Pautz 2011: 423;Seabrooke and Tsingou 2014). Their need of 'usable knowledge', that is 'accurate information that is of use to politicians and policy makers' (Haas 2004: 574) spectacularly increased, think tanks becoming important actors in the global and European 'knowledge regime' (Campbell and Pedersen 2014;Pautz 2011).
Against this backdrop, I argue in this article that the crisis was an opportunity for Brussels-based think tanks to build on their recent experience and to transform constraints into opportunities. The leading think tanks quickly understood that the risk of disintegration and the problems of the euro pushed them to be become producers of ideas rather than disseminators of opinions produced elsewhere. The context was no longer appropriate to prise the virtues of the euro without solid arguments. What was at stake was to legitimize decisions through new means. The crisis opened a window of opportunity as it questioned a series of well-established ideas with regard to the functioning of the Economic and Monetary Union (EMU) and the euro. Thus, in the first crucial years of the eurozone crisis, powerful think tanks sought to shape policy through intellectual arguments. While in the past a good think tank was, in the best cases, an 'incubator of ideas', whose aim was to host 'seminars, round-tables, book-launches, debates and a range of social events' (Boucher et al. 2004: 45), the eurozone crisis has pushed these organizations to do more in order to be relevant. Dissemination, synthesis and repetition of policy analysis was no longer sufficient in the Brussels bubble (Stone 2007: 273). Research was the new key to open the world of power and to legitimize a new set of arguments to douse the flames of the crisis.
Think tanks are far more strategic than simply acting as a 'bridge' (Stone 2007: 273). When the crisis was 'hot', they managed to considerably increase their budgets; on the other hand, they strategically enlarged their networks competing for audience. The network expansion became a differentiation strategy intended to strengthen think tanks' reputation and credibility and driven by the professional trajectory of think tanks' affiliated members. While some experts connected with American economists and international financial organizations, others have strengthened their links with economists in the EU-28. Think tanks' directors and researchers have used their personal contacts to involve in the production of reports new experts with strong credentials, excellent reputation, and flawless credibility. As this article will show, those who populate these professional milieus have in common different forms of symbolic capital: academic authority; professional prestige; reputation for personal expertise; academic degrees; etc. They are 'multiple insiders' in the sense that they are connected to a wide range of institutions and professional networks, including the policy-making field (Henriksen and Seabrooke 2016: 2). Their increased professional mobility gives them access to the 'international centres of epistemic power' (Helgadóttir 2016: 2).

Bruegel and the CEPS in the Brussels agora of ideas
There are 149 think tanks in EU affairs, some based in Brussels, others in the capitals of EU member states (Boucher et al. 2004;Missiroli and Ioannides 2012). Since the beginning of the eurozone crisis, only four of them have been constantly mentioned by experts and decision-makers as visible and relevant in current debates: the European Policy Centre (EPC); Friends of Europe; Bruegel; and the CEPS. While the EPC and Friends for Europe are appreciated for their ability to network with stakeholders and political actors (Missiroli and Ioannides 2012: 10), the CEPS and Bruegel are esteemed for their in-house research and ability to propose policy recommendations based on data and rigorous analysis.
The CEPS and Bruegel had been established by leading economists who worked in EU institutions, often at the European Commission, as well as in a wide range of international organisations, such as the IMF and the WB. The CEPS was created prior to the establishment of the EMU, in 1983, 2 when Jacques Delors was President of the Commission and Daniel Gros (director of the CEPS), who worked for the IMF, was as an economic advisor at the Commission. Bruegel was founded in 2005 by Jean Pisany-Ferry, when the first problems of the eurozone area were discussed at the EU level, as neither France nor Germany were able to fulfil the conditions of the SGP. 3 Jean Pisani-Ferry intended to change the Brussels-based landscape, setting new ambitions for think tanks dealing with European issues. Bruegel sought to be more critical than its counterparts. As Pisani-Ferry said in 2004, the aim of Bruegel was not to 'jump into the Stability and Growth Pact debate', but rather to 'bring a European perspective to global issues and a global perspective to EU issues' (Politico 1/19/2005).
While Bruegel was onward-looking, seeking to connect the European and the global, the CEPS was inward-looking and connected with EU member states. They were established with the aim to persuade policy-makers to take their ideas on board and eventually to shape the agenda of EU institutional actors. To do so, they sought to improve the quality of economic policy through debate and evidence-based research. Since their establishment, Bruegel and the CEPS are the only Brussels-based think tanks occupying leading positions in international rankings. In 2014, the latter was ranked number two in the world and the CEPS number eight on the list of 'top think tanks worldwide' (non-US) (McGann 2015). The same study concluded that Bruegel and the CEPS were among the 18 worldwide think tanks with the most significant impact on public policy. In 2016, the Global Go to Think Tank Report (GTTI, McGann 2015), which is issued by the University of Pennsylvania and scrutinises the activity of 6,846 think tanks, ranked Bruegel number 1 (worldwide) for the best concept and new paradigm and placed it on number 2 (worldwide) in the top ranking of international economics think tanks. The CEPS was also ranked among the top-ten 'Think Tanks Worldwide', moving up two positions compared with the previous year. According to senior research economists from Bruegel and the CEPS, these two think tanks are the only ones worthy of the name in Brussels.

What do crises do to think tanks?
At the beginning of the eurozone crisis, Brussels-based think tanks had to adapt their behaviour to the new context and to redefine their strategy rapidly. The crisis challenged decision-makers, experts, researchers and observers to leave their comfort zone and to put forward new ideas. When the crisis entered into its fast-burning phase in 2010 with the beginning of the Greek crisis, in search for solutions, EU institutional actors relied heavily on expert knowledge. Although each EU institution has its own office in charge of policy prospection, in 2010 the proportion of in-house academic expertise was relatively reduced. Against this backdrop, Jean-Claude Trichet and Mario Draghi stressed the importance of 'scientifically-informed monetary management' (Mudge and Vauchez 2015). Not only technocratic institutions like the European Central Bank (ECB) seemed to be inclined to use external expert knowledge, but also the Commission, as well as directly and indirectly elected institutions such as the European Parliament (EP) and the Council sought to boost their legitimacy by calling upon sustainable economic expertise when appropriate. As the debt crisis in Greece worsened, the ECB established its own research unit, delivering with regularity a wide range of studies and reports (Mudge and Vauchez 2015). The Commission increased its staff at the Directorate-General for Economic and Financial Affairs (DG ECFIN). The Research Department of the EP amplified its collaborations with research centres and universities across Europe. It also increased its staff, hiring in particular academics holding a PhD degree in the field of social sciences. Finally, high-level officials in Brussels engaged in discussions with renowned American and European economists such as Paul Krugman and Thomas Picketty.
As far as Brussels-based think tanks are concerned, their directors and research teams have often been invited by officials to speak at meetings in EU institutions. According to interviews, while the members of Bruegel are often invited to informal discussions organized prior to Economic and Financial Affair Council (ECOFIN) meetings, CEPS's researchers are frequently asked to attend meetings with Commission's officials and representatives of the ECB (interview, senior researcher, CEPS, 22 September 2017).
The eurozone crisis put Brussels-based think tanks in the spotlight, giving them more visibility than ever before. According to interviews, it prompted vivid internal debates on how think tanks should play their role in this particular context. It goes without saying that the crisis has reshaped their research agenda in terms of expert knowledge production. Both the CEPS and Bruegel proved able to react rapidly and offer data-driven analyses to decision-makers.
In 2010, as one of the interviewees stated, 'research became the new word in the town' (interview, senior researcher, CEPS, 21 September 2017). Facts, research, data and findings have become the new standards to be reached by Brussels-based think tanks. The CEPS and Bruegel aspired to do what their American counterparts seek to achieve: to generate new ideas with the aim to eventually shape policy. As Daniel Gros, director of the CEPS, recently put it: 'the role of la think tank is to provide policy-makers with analysis and expert opinion, based on facts, figures and rigorous research'. He added: 'If European think tanks are to retain their value, their role is not to be a cheerleader of European integration, but rather to provide facts, figures and an array of informed policy options to EU decision-makers'. 4 Under the leadership of their directors, the CEPS and Bruegel have developed medium-term research projects, while providing autonomy to their researchers in identifying new topics (interview, senior researcher, Bruegel, 18 August 2017). Research was crucial, but what was even more important was how to repackage research findings for policy-makers and how to make informed policy recommendations (interview, senior researcher, CEPS, 21 September 2017). Both Bruegel and the CEPS have been active (proactive and reactive) in constructing narratives about underlying causes and in proposing solutions to strengthen its legitimacy and to solve Europe's economic problems. The production of expert knowledge within Bruegel and the CEPS has witnessed several stages: framing the causes of the eurozone crisis; identifying solutions as well as proposing alternative views on the crisis; and assessing with a critical eye the decisions taken at the EU level. As Figure 1 shows, the number of reports spectacularly increased in 2010 to reach its highest point in 2011 for Bruegel and in 2012 for CEPS.
Some reports have been produced at the initiative of resident and non-resident researchers, while others have been commissioned by EU institutions (the EP in particular) and other stakeholders. As one interviewee stated, 'when the president of the ECB came to the EP to discuss the situation in Greece, MEPs felt the need to have an expert background note' (interview, senior researcher, CEPS, 21 September 2017). Thus, at the request of the Committee on Economic and Monetary Affairs of the EP, the CEPS has written a series of reports on the European Semester and participated to a series of public hearings at the EP on the institutional aspects of the economic governance born from the crisis. Concerning Bruegel, while some reports were to inform decisions and discussions in the EP's Committee on Economic and Monetary Affairs, others had been required by the Committee on Employment and Social Affairs, dealing with the impact of austerity policies in the EU. As the interviewees stated, some EU institutions were more dependent than others on external expertise. Researchers from Bruegel and the CEPS perceived the Commission as being 'more independent, more autonomous thanks to the expertise provided by the DG ECFIN' (interview, senior researcher, the CEPS, 21 September 2017). In contrast, the EP was dependent on external expertise, but at the same time 'more open to consider a variety of views and opinions' (interview, senior researcher, the CEPS, 21 September 2017).
On the other hand, the crisis has been an opportunity to obtain more financial resources. Bruegel is one of the few (if not the only) Brussels-based think tank to be financed by a dozen governments. Like many of its American counterparts, it depends very little on public funding as it is financed through members' subscriptions, which constitute more than 85 per cent of the annual budget. 5 In contrast, the CEPS's research activity is to a large extent supported through EU grants, like many European universities who compete for funding by putting together competitive research projects and consortia. In the case of Bruegel, less than 15 per cent of the budget comprises grants from EU institutions. In contrast, over recent years, the CEPS managed to submit a wide range of research projects and to considerably increase its budget. The membership share of the CEPS budget varies between 20 per cent and 30 per cent from 2010 onwards. In 2011, it was co-ordinating several FP7 EU projects with a total of 80 partners in Europe. A considerable revenue resource was also derived from the studies and briefings commissioned by the EP.
Thus, in 2011, Bruegel's (2012: 19) budget revenue was €3,948.289, while the CEPS budget was €8.6 million. In 2012 the CEPS earned a total of €9.2 million and could employ 'more researchers than ever before', as stated in its activity report. The same year, Bruegel reported revenues in an amount of € 3,831.311 (with €442.149 income from public organizations, EU institutions, IMF and the Peterson Institute). Although their budgets were not comparable to the Peterson think tank in the United States, which, according to one of the interviewees, 'has unlimited resources' (interview, senior researcher, Bruegel, 18 August 2017), at the beginning of the eurozone crisis the CEPS managed to obtain a revenue up to €9 million, which represents 80 per cent of the Peterson Institute budget in 2015 ($12.5 million). In 2016, while the budget of the CEPS was €7.6 million, Bruegel's budget was about €4.5 million. One should note that the same year the third biggest Brussels-based think tank budget was that of the EPC: €2,293.980. The gap between the revenues of CEPS and Bruegel, on the one hand, and other Brussels-based think tanks, on the other, widened considerably in the context of the eurozone crisis. Both Bruegel and the CEPS use two thirds of their annual budget to cover remunerations and social charges.
How do think tanks expand their networks in times of crisis?
In the context of the crisis, the vast majority of reports have been produced by the epistemic core of Bruegel and the CEPS as illustrated in Figure 2.
In addition to the increased productivity within the Bruegel and the CEPS, think tanks expanded their networks. The interviewees declared that the expansion of networks was a deliberate internal strategy encouraged not only by the boards of directors and the scientific councils, but also by individual initiatives taken by resident and non-resident researchers. Prior to the crisis, Bruegel had already had strong links with academics, in particular American, as in the United States there is a tradition of interactions between the world of decision-makers and the world of academics. In Europe, the direct involvement of academics in providing policy recommendations to decision-makers has always been perceived as a threat to academic independence. However, the devastating consequences of the eurozone crisis pushed academics to take more critical stances and to engage in public debates about the failures and the future of the eurozone. Academic collaborations with think tanks increased. Drawing on experts' CVs, it appears that 51 per cent of those associated with Bruegel's research hold a PhD, which is comparable to the proportion of researchers holding a PhD involved in the CEPS's activities (49 per cent). American Universities (Columbia University, Harvard University, the Massachusetts Institute of Technology, the University of Chicago, Yale, Princeton, Stanford, Pennsylvania) are well-represented as alma maters of Bruegel's associated researchers and experts. In contrast, while a few of those who contributed to the production of knowledge within the CEPS received their PhD from a leading American university, the majority hold a PhD awarded in Europe.
Credibility and reputation were key in their deliberate strategy of network expansion (see Figure 3). To achieve this, resident researchers from the CEPS and Bruegel have used their own networks and contacts. As one interviewed stated, both 'Sapir and Pisani-Ferry are in their late 50s. They have contacts. They have expertise. They have also personal credibility. They have good networks (institutional and academic)' and they have heavily relied on them in the context of the crisis. Thus, Nicolas Véron 6 and André Sapir from Bruegel helped to strengthen the links with the Peterson Institute for International Economics in Washington and the World Bank (in particular with Anne Osborn Krueger, former World Bank Chief Economist and professor at the John Hopkins School of Advanced International Studies in Washington), while Jean Pisani-Ferry used his contacts to strengthen links with the IMF (interview, senior researcher, Bruegel, 18 September 2017). Bruegel's academic production implied the diffusion of ideas of prominent academics in the field of economics and finance, including Raghuram Rajan, who predicted the crisis and who served as head of the Reserve Bank of India, and Carmen Reinhart, one of the most-cited Harvard economists. Marek Belka, who in 2008 was appointed director of the IMF's European Department, was also associated with the production of policy solutions and recommendations by Bruegel. Askoka Mody (Bruegel) advised different governments on financial policies and projects. He served as deputy director of the Research and European Department of the IMF. Indhira Santos, senior economist at the WB, was a research fellow at Bruegel between 2007and 2009. Garry J. Schinasi joined Bruegel in 2009 during his sabbatical from the IMF. The trajectories of Santos and Schinasi illustrate how Bruegel acted as a bridge between the United States and Europe for economists with global reputation who came to Brussels after or before having worked for IMF and WB.
In contrast, the CEPS developed its network in connection with a variety of European universities and economists, partly owing to its participation in research projects financed by the EU. Since the beginning of the crisis, several papers have been co-authored with European academics (interview, senior researcher, the CEPS, 21 September 2017). Besides advising high level political actors, both Bruegel and the CEPS have also developed professional connections with domestic research institutes such as the German Council of Economic Experts, the Council of Economic Analysis to the French Prime Minister and the French Council of Economic Analysis.
Although the expansion of networks reflects the membership structure of Bruegel and the CEPS, data show that it is also facilitated by the high degree of professional mobility. Drawing on CVs and biographies, data show that as far as Bruegel is concerned, the group of those having experience with international financial institutions is higher that the group of those who have worked for EU institutions. Only a minority, including Guntram B. Wolff (Bruegel) and Daniel Gros (CEPS), has worked both in EU as well as in international organizations. Another significant proportion of experts served as advisors to EU officials, presidents of EU member states and ministers. Bruegel's intellectual epistemic power finds its origins in its connections with the United States, while the CEPS seeks to bring together expert knowledge from the EU-28. This could reflect two different patterns in the production of economic expert knowledge, one more engaged in global economic debates, the other drawing its ideas from European traditions and economic models.

Why?
By expanding their networks, Bruegel and the CEPS have pursued a differentiation strategy. More than engaging with the policy process, in the context of the eurozone crisis they have sought to produce 'relevant research', as research was precisely what distinguishes a think tank from others (interview, senior researcher, CEPS, 21 September 2017; interview, senior researcher, Bruegel, 18 September 2017). While the majority of those operating in Brussels are able to organize events and to bring together decision-makers and academics, only the CEPS and Bruegel have the reputation for producing quality policy analysis. They also perceive themselves as being 'the only ones that can be critical, that have something new to say and that can engage in a serious dialogue with decision-makers' (interview, senior researcher, Bruegel, 18 September 2017). Without doing research, the organizations risk to be nothing more than an 'outlet to organise events' (interview, senior researcher, the CEPS, 21 September 2017). However, the network expansion and the budget increase widened the gap between these two leading actors and the other Brusselsbased think tanks which, according to interviews, are not able to produce 'quality papers', 'to compete' and 'to be bold as to say a number of things' (interview, senior researcher, Bruegel, 18 September 2017).
Both the CEPS and Bruegel sought to become leaders on specific topics. As one interviewee stated, while the CEPS conducted research on risk sharing, Bruegel paid more attention to banks (interview, senior researcher, CEPS, 21 September 2017). If in the past Bruegel was created because at that time the existing think tanks were not 'particularly influent or original' (Politico, 19 January 2005), since 2010 both the CEPS and Bruegel have been keener to stir things up. In the context of the eurozone crisis, collaborating with academics was an attempt to be 'different' (interview, senior researcher, CEPS, 21 September 2017), to be more than a 'talking shop' and to produce new ideas and solutions on key policies for the integration process. What distinguishes a think tank from an academic institution is not always the degree of (hyper)specialization in a specific field, but the ability to anticipate discussions and to react very fast (Boucher et al. 2004: 37). To what extent these reports have reshaped the decision-making process is another story, more difficult to capture.

Conclusion
This study on expansion of the Brussels-based think tanks' networks in times of crisis is among the first of this kind. While the article shows when, how and why think tanks expand their networks, it also sheds light on how the eurozone crisis has been an opportunity for them. The article shows that both the CEPS and Bruegel have managed to adapt rapidly to the changing context, to act strategically by involving more researchers than ever before in the production of their analyses ( Figure 1) and by increasing their budgets and networks so that more researchers can fuel their thinking on the failures and the future of the euro and the EMU (Figure 2 and 3).
In the context of the eurozone crisis, research has become a mark of differentiation that think tanks have used in order to strengthen their credibility, reputation and intellectual productivity. As Stone put it, since the 2000s, think tanks are more equated with a policy research function (2007: 4). While at the moment of their establishment their main issue was to 'disseminate' research, (Sherrington 2000: 174), this study shows that since 2010 the two leading Brussels-based think tanks have managed to become producers of expert knowledge and usable academic research. Besides producing research, the role of the CEPS and Bruegel is to connect two agorae of ideas: one is global and it is maintained by the latter, the other one is European and it is supported by the former. As the visualization in Figure 3 shows, these two thinks tank are not two isolated islands. The strategic expansion of networks creates bridges between transnational policy spaces (Stone 2013) and Brussels-based think tanks. By looking at the expansion of networks, this article reflects the contours of these spaces and shows how those who populate them are connected through each other via their professional background. The expansion of networks illustrates the hybridity of political spaces (Georgakakis and Rowell 2013) and the connections between the global and European professional ecologies. Further research is needed to analyse to what extent EU policy-makers rely on the analyses and ideas produced by the transnational ecology of Bruegel and the European one of the CEPS.

Disclosure statement
No potential conflict of interest was reported by the authors.