The proliferation of courts, tribunals, and other dispute settlement bodies is a remarkable feature of the international political and legal landscape. Scholarly interest has grown accordingly, evolving from the careful analysis of particular institutions to ambitious efforts to theorize, compare, and gather data across a broader range of them. Work in this area has focused variously on the origins, design, and effects of international courts (ICs) and is quite diverse in terms of methodological and theoretical approaches. It is also an area where political scientists and legal scholars engage each other’s work routinely. The result is a rich and productive stream of research.

The Performance of International Courts and Tribunals is motivated by a specific and important puzzle: ICs vary dramatically in their level of activity, their efficiency, and their broader contributions to global governance. The editors capture these concerns with the concept of “performance.” By engaging existing literatures on regime effectiveness and international organizations (IOs), they succeed in linking the study of ICs to broader debates in international relations that have occupied scholars for many years. Moreover, by incorporating the types of questions and analysis that are more typical of the international law (IL) field, they are able to bridge the IR and IL disciplines quite successfully (indeed, the contributors to the volume are almost equally divided between political science and law).

An introductory chapter, coauthored by the editors, provides a framework for evaluating and explaining the performance of international courts and tribunals. This framework is then applied across 10 substantive chapters, divided into two parts. The authors in Part I assess IC performance in particular issue areas, with chapters on trade (Cosette Creamer and Anton Strezhnev), investment arbitration (Daniel Behn), human rights (Dinah Shelton), and international criminal courts (Nabuo Hayashi). Part II then turns readers’ attention to an explanation of performance, mostly by identifying certain factors that are important but underexplored. Although some of these chapters focus on specific institutions (e.g., Hyeran Jo, Mitchell Radtke, and Beth Simmons focus on the International Criminal Court), most identify a particular determinant or mechanism of performance and consider its effect on some class of ICs. Thus, we have chapters on judicial fragmentation and overlap (Benjamin Faude), on the judicial practices of judges (Jeffrey Dunoff and Mark Pollack), on the socialization strategies of ICs (Nicole de Silva), on compliance mechanisms (Chiara Giorgetti), and on the underlying problem structure of an issue (Steinar Andresen). The volume ends with two concluding chapters, one by Theresa Squatrito on methodological considerations and one by all four editors that summarizes the findings and discusses the future of ICs and related research.

A valuable contribution of the volume is the analytical framework supplied in the first chapter, which offers a road map for research on ICs. The editors build on a conceptualization of performance by Tamar Gutner and Alexander Thompson (“The Politics of IO Performance: A Framework,” Review of International Organizations, 5(3), 2010) that focuses on both process and outcomes as important dimensions for understanding organizational performance. The editors go further by supplying a number of specific criteria—some linked to process and others linked to outcomes—for analysts to use when assessing the performance of international judicial bodies. When they turn their attention to the determinants of IC performance, the editors do not attempt to provide a single theory or even to generate specific hypotheses. Instead, building on the IR and IL literatures, they theorize a range of factors that could matter in different circumstances and at different levels of analysis. Overall, the theoretical framework is sufficiently focused to guide the subsequent chapters and produce a coherent edited volume. At the same time, the framework is flexible enough to give the authors room to explore and deviate in interesting ways—which they certainly do.

The diversity and overall quality of the substantive chapters is excellent; they offer insights that will be interesting and novel even to mavens of these institutions. Some are quite ambitious empirically. For example, to study whether the International Criminal Court (ICC) successfully deters war crimes, Jo, Radtke, and Simmons combine cross-national data on the visibility and domestic imprint of ICC law with a detailed study of its impact in Uganda, looking over time at the relationship between different types of ICC intervention and attacks on civilians. Behn offers a creative approach to assess the performance of investment arbitration, which is complicated by its decentralized patchwork of treaties and tribunals. He presents a number of indicators that allow him to assess performance related to access, outcomes, and process, using systematic data to evaluate some common (but often untested) complaints about the regime’s effectiveness and fairness.

Other chapters are notable for their theoretical contributions. De Silva extends constructivist research on socialization to consider how ICs might use strategies to socialize key audiences into the court’s norms and procedures. Dunoff and Pollack apply “practice theory” to examine the evidentiary and fact-finding practices of international judges, an aspect of process performance that is often informal and draws little attention. Moving to the macro level, in their respective chapters Faude and Andresen push us to think about ICs in their broader institutional context. Performance is affected by the degree of overlap and interaction among ICs (Faude), and in almost all cases we need to consider the court’s role in a broader regime to understand its causal impact on outcomes (Andresen). To varying degrees, all of the authors apply but also extend the volume’s theoretical framework in new and fruitful directions.

As a whole, the volume grapples with a number of methodological obstacles to studying performance systematically. For any given IC, knowing what to measure and how to measure it can be challenging. Even some common metrics, like compliance, are difficult to define and operationalize (as Creamer and Strezhnev demonstrate effectively in their discussion of trade disputes). Establishing a causal link between the activities of ICs and outcomes of interest is even trickier, especially given the presence of countless factors beyond the control of courts. The volume highlights these problems, and the penultimate chapter, by Squatrito, provides a thoughtful discussion of methodological issues and useful guidance to researchers.

In the end, there are many valuable insights and important lessons for studying IC performance, although the volume does not deliver a set of general conclusions based on the findings. Because each court is so different, and because the authors investigate different aspects of performance, the editors have limited opportunities to generalize. As they concede in their concluding chapter: “This extreme diversity makes it difficult to engage in systematic comparisons regarding the performance of international courts and tribunals” (p. 408). This raises the question of whether the scope of the volume is too broad, with the inclusion of many disparate issues and types of institutions. At this stage of the research agenda, this broad scope is appropriate, although future work will likely focus on more specific aspects of performance or narrower empirical domains.

There are contemporary issues that probably require more attention from scholars working in this area. First, the role of power deserves more analysis, especially the question of whether courts need the support of powerful states to be successful. With the United States withdrawing from many international institutions, this issue is increasingly important. Second, the role of domestic politics merits more attention. The current, populist backlash against investment arbitration and the European Union, as well as other feared threats to sovereignty, could erode the legitimacy and thus performance of ICs over time. Those inspired and guided by The Performance of International Courts and Tribunals will be in a better position to study such issues in a systematic and politically interesting way.