The papers in this special issue illuminate some of the central animating questions of comparative health policy research. The first of these questions concerns why we compare. Is it to explain or to prescribe the adoption of particular policies? Call this the explanatory/prescriptive question. The second concerns how we compare. Do we undertake pattern-recognition or model-testing? Call this the inductive–deductive question. The third question concerns what our comparative studies are finding. Are nations becoming more similar in their health policy frameworks or is each national framework shaped by its institutional legacy? Call this the convergence/path dependency question. In fact, none of the papers answers these questions in either/or terms; and together they demonstrate the rich mix of considerations (as well as the lack of resolution) that characterize the field.

Sometimes, these three types of questions tend to align (though imperfectly), with each other and with some disciplinary boundaries. Empirical economists and management scientists typically start with a research question or hypothesis that is generated by (deduced from) a more-or-less formal theory or model of how the elements of a policy relate, and then test that hypothesis against observations in different nations. Such economic or management models often lead to policy prescriptions and hence to encourage some policy convergence across nations. Political scientists, sociologists, historians and others are more likely to draw from detailed contextual description of various nations to identify patterns of elements that have an impact on policy, often generating typologies according to which different nations can be classified. Such typologies are more likely to be associated with arguments for continuing policy divergence. This alignment is far from universal – political scientists, sociologists and other build and test formal models of behaviour; empirical economists may test a broad range of factors in an essentially inductive route to model-building; and findings of convergence or divergence are not exclusive to any approach or discipline. Nonetheless, these general tendencies provide some perspective on the comparative public policy project.

Each of these papers has an interdisciplinary team of authors, and each investigates experience with a policy that has its base in a deductive economic or management model (choice-based policies, activity-based hospital payment, comparative effectiveness assessment, integrated care for chronic disease and a shift to governance through regulation of economic actors). Each paper seeks to explain experience with these policies in different nations – notably the divergences between actual results and what would be expected on the basis of the original economic and management science models. Building inductively from descriptions of national experience, they find a degree of convergence across nations in the formal dimensions of policy (in effect, a following of the prescription) but a continuing divergence in application along paths shaped by distinctive national institutions and histories. This question of the extent of convergence on a more-or-less common pattern, and the correspondence of the resulting experience to prescriptive policy models, is likely to drive much comparative policy analysis in the foreseeable future.

What, in the end, does our endeavour tell us about the range of the possible for health policy – our mutual focus as health policy scholars, whether our goal is explanation or prescription? Optimistically, let me suggest that the comparative project is leading to a more nuanced understanding of the scope and limits of the possible in particular nations, in ways that can inform the policy debate. Consider as one example how comparative analysis might inform the contemporary debate in the United States around the implementation of the Affordable Care Act of 2010. Various elements of this mosaic set of changes have analogies elsewhere. Our growing understanding of the factors that affect the implementation of, for example, risk-adjustment mechanisms, comparative effectiveness research, reliance on arm's-length agencies, non-fee-for-service models of provider reimbursement and other aspects of the American reforms can calibrate expectations and suggest implementation strategies in the US context. To do so will mean overcoming naïve enthusiasm for the uncritical importation of practices from abroad on the one hand and nativist cynicism about the potential for such elements in the unique American context on the other.

Comparisons across time within nations can marry well with cross-national comparison in this regard. The Dutch experience in moving by stages over 20 years to a universal framework of governance based on the regulation and subsidization of competing insurers contrasts with abortive attempts to introduce a somewhat similar framework in several US states, also using a staged process of adoption, in the 1990s. Comparing these cases, we learn that sustaining a regulation-based governance framework over the long time period needed to develop and refine the necessary regulatory instruments requires more consensual political institutions and processes than are typical in the American context. In that light, the decision in the recent federal health reform process in the United States to confine the ‘managed competition’ approach to the small-group and individual market, at least at the outset, appears more realistic.

In the end, the comparative study of health policy is a dance – between explanation and prescription, between inductive and deductive analysis, and between attention to converging elements and attention to the continuing distinctiveness of each nation. As we compare across time and nations – shall we dance?