Should the European Commission be viewed as a bureaucratic institution driven by technocratic problem solving or as a fundamentally political institution in which intra-institutional power and/or ideology determine policy outcomes? Miriam Hartlapp, Julia Metz, and Christian Rauh address this important issue via examination of a sample of the policy changes—mostly directives—that the Commission proposed during the Prodi and Barroso Commissions (1999–2010). The analysis employs process tracing via extensive document analysis and 137 structured interviews on 48 proposals in three policy areas—the intersection of common market and social policy, research and innovation policy, and consumer policy—where the proposals fell within the responsibility of two or more Commission directors general (DGs).

In each case, the authors examine the forces that influenced both the draft proposal developed by the DG assigned initial responsibility and the final proposal reached when other Commission actors disagreed with the first draft. The authors’ most general finding is that initial drafting is largely dominated by technocratic considerations focused on problem solving. But when other DGs disagreed with the initial draft, political considerations in the form of either intrainstitutional competence seeking, more frequently, or ideology, less frequently, dominated the revision of draft proposals. They conclude, then, that the European Commission cannot be simply or easily assigned to any one of the three competing caricatures offered in earlier scholarship.

The analysis proceeds in several steps. The first four chapters introduce the topic by providing admirably comprehensive reviews of both the long-standing debate over the nature of the Commission and the many prior hypotheses on the factors guiding position formation within it, along with a clear guide to the methodology of the analysis. The next three chapters present the case studies of the 48 proposals across the three policy domains, respectively, with similar policies within each area grouped and then discussed in four to six pages. Chapters 8 through 9 isolate, respectively, the roles of technical information, public opinion, and bureaucratic structure across the three sets of case studies in determining the initial drafts of the proposals and how they changed as they emerged from debates within the Commission. The last three chapters return to the larger question of what determines Commission proposals, first by looking across all of the cases to examine the relative importance of the many forces hypothesized to influence Commission decision making and then by considering how their case findings bear on the central question about the nature of the European Commission.

Hartlapp, Metz, and Rauh’s analysis has a number of admirable strengths beyond its attention to perhaps the most contentious question about the nature of the European Commission as a political institution. Four deserve special note. First, and most obviously, the analysis goes a long way toward opening up the black box of Commission decision making by rejecting as part of the authors’ research design the common assumption that the Commission is a unitary political actor. Second, the first several chapters provide an essentially encyclopedic review of prior scholarly work on the Commission. Indeed, they identify 20 variables (p. 28) hypothesized in prior work to influence Commission decision making, variables including, among many others, the partisan ideology and career experiences of the actors, the salience of the policy issue in the media, the roles of expert groups and interest organizations, and the role of prior legal decisions bearing on a proposal. Third, the authors’ analysis is especially attentive to the role of the status quo in establishing a counterfactual against which to assess the degree of policy change being proposed. And fourth, the deep and highly structured process tracing conducted on the 48 cases provides both a rich resource with which we might assess policymaking within the Commission and an instructive model on how such middle-n research should be conducted.

These attributes will make this work essential reading for those interested in European Union political institutions. This especially will be true for younger scholars seeking to step into the deep and rapid torrent of work conducted on the European Union.

At the same time, however, the analysis has two limitations. Starting with the least important, by examining only proposals that fall across the competencies of two or more DGs, the analysis does not consider a full sample of Commission proposals. Those considered within a single DG are ignored. The authors’ reason for limiting their sample is clear: Conflicts between and among DGs plausibly provide an especially good laboratory in which to observe the forces guiding Commission decision making. But such analysis cannot be used to determine what kind of animal the Commission is across its full array of policy actions. This does undermine what the authors did accomplish with respect to conflict between and among DGs. But it modestly limits the scope of their findings with respect to the nature of Commission decision making more generally.

A much more serious limitation concerns inferential validity. At points, the authors seem to abjure any claim of conducting an explanatory exercise, noting that their work is best viewed as a “plausibility probe” of the causal role played by the 20 independent variables influencing Commission proposals (p. 31). Similarly, on page 36, they write that their case studies “are not designed to test competing hypotheses against one another.” In the larger context of the book, however, these statements seem a bit of a dodge to shield the design from potential criticism. Indeed, in the very next sentence (p. 36), the authors write: “The cross-case comparison allows inferences to be drawn about the relative explanatory power of the factors and mechanisms identified as relevant.” And, in fact, the last three chapters of the book make a number of quite specific causal claims about the relative importance of the causal forces examined. One cannot have it both ways.

Can the research design support those causal claims? In their discussion of the 20 hypothesized independent variables, the authors note that nearly all interact with others. And many of them almost certainly will be collinear with each other. With 20 independent variables, many plausible interactions, and likely collinearity, 48 observations is not sufficient in terms of statistical power to validly account for rival explanations. This is obviously the reason that the authors did not attempt to construct and test a full econometric model. But this is not the only way to validly test competing hypotheses. Instead, selective comparison of essentially similar cases differing on only one of the hypothesized influences could have provided a strong basis for making inferences in the manner of a quasi-experimental comparison group design. Yet the authors essentially avoid such focused comparison of cases in lieu of reporting central tendencies across seemingly similar cases. As a result, their many claims about which variables are most determinative of Commission decisions can too readily be dismissed because the analysis does not meaningfully control for the influence of rival hypotheses.

Yet despite this serious limitation of the analysis as an explanatory exercise, Which Policy for Europe? will be of considerable use to scholars studying European political institutions. The richness of the cases, the clear explication of the interpretative conflicts in the literature, and its diving into the internal dynamics of Commission decision making will make it essential reading for European Union scholars. But a more compelling explanatory account of Commission decision-making must await further research.