This book is the product of a multi-year collaboration led by Christoffer Green-Pedersen and Stefaan Walgrave. Drawing on the work of John Kingdon, Frank Baumgartner, and Bryan Jones, this book starts with the premise that political attention is a scarce resource, with large consequences for policy outputs. The project then develops a methodology to study agenda setting systematically, and applies this methodology to eleven country studies. In each country case, we see how different issues rise and fall in prominence in the post-War period. How do elections, party competition, and the alteration of parties in government change the national agenda? And what happens to policy agendas when there is major institutional change, and a party system experiences collapse (as in Italy), devolution (as in Belgium and Spain), or reunification (as in Germany)?

Before turning to the answers to these critical questions, a word on the methodology of this project. In many ways, this project represents comparative research at its best. To tackle a very broad question—how issues such as the economy, immigration, trade, and crime rise and fall in prominence across rich democracies—the editors brought together many national teams. What distinguishes this project, and makes for an unusually coherent edited volume, is that the teams not only used a shared methodology, but also a shared codebook, refined over several years. The result is an unusually coherent edited volume, each of whose chapters is clearly written and easy to follow. This is a remarkable achievement, because in comparative politics knowledge does not cumulate easily across countries, issues, and time-periods. Moreover, the underlying data on both political statements (e.g., manifestos) and government actions (e.g., laws) is publically available on a series of national websites. This will help many more scholars join in the debate, combine this data with other data, perhaps criticize and refine concepts, and in general multiply the impact of these scholars’ painstaking work.

So what have we learned about agenda setting substantively? In summarizing eleven country cases, the editors conclude that “parties do not pursue systematically diverging agendas” and that “institutional change does lead in some instances to shifts in issue priorities, but these shifts are often small” (p. 226). It is to the credit of the editors that they have summarized all the chapters clearly, and reported a series of “no effect” and “small effect” in a synthesis table (p. 223). That said, these are shocking findings, given how fierce electoral competition appears, how central parties are to our explanations of political outputs, and how major some of the institutional shifts studied loom.

But are these very surprising findings correct? Can it be the case that alternation of parties in government makes a small difference even in a country like the UK, whose electoral rules make it a paradigm of responsive and accountable government? And can it be that earthquakes in terms of institutional design—such as German reunification or Italian party collapse—matter much less than previously thought? Two very plausible explanations for this paradox are offered by way of conclusion, but are not systematically tested. One theory is that of “issue intrusion”: parties start with ambitious ideas, but once in office, they have to deal with the issues of the day. The second theory is that of party-competition—once a party claims an issue that resonates with the electorate, other parties move quickly to copy it. The example of immigration restrictions is especially supportive of this argument. Individual chapters offer a third potential explanation—Europeanization. This is the suggestion that the volume of European Union directives to be transposed into national legislation is so large, that individual EU governments no longer have real control of the agenda. Each of these hypotheses is fascinating, and deserves greater systematic exploration.

Another explanation, however, is that the measures used are not perfect for the task at hand, and still need further refinement. Based on my priors, I am very surprised when told that German reunification made a minor dent in Germany’s legislative agenda, or that the match between government priorities and legislative output changed very slightly when Italy experienced a sharp shift towards majoritarian rule, or when Spain increased the power of regional governments. I am particularly concerned about the validity of data on government output, and how laws of very different substantive importance are aggregated. That said, the authors of this project have many ways to explore and set aside this concern about validity. It should be very possible to compare the comparative agenda data with existing datasets, including the comparative manifestos project and expert survey scores, and to qualitatively analyze data subsets when discrepancies arise. The other major untapped potential of this project concerns cross-country comparisons. In sum, we benefit tremendously from this cross-country collaboration of unusual rigor and scope, and already have a set of intriguing conclusions before us. Because the authors have made so much material publically available, potential additional exciting findings are now low-hanging fruit.