INTRODUCTION THE CHALLENGES OF CLASSIFYING WELFARE STATE TYPES: CAPTURING THE PRODUCTIVE AND PROTECTIVE DIMENSIONS OF SOCIAL POLICY John Hudson and Stefan Kühner ± , University of York, United Kingdom 1. Introduction: the Dependent Variable Problem A growing number of comparative studies in social policy have addressed ques­tions surrounding the reliability and validity of macro-quantitative approaches, in­dicating an increased awareness of what has been called the‘Dependent Variable Problem’ of comparative welfare research. As Kühner(2007) has shown, this is more than a minor technical or methodological problem for the most commonly used social expenditure-based measures of‘welfare state change’ often produce conflicting answers to key research questions about the nature of recent processes of welfare state change. Although there has been much progress in attempts to re­solve weaknesses in key macro-level measures of welfare state effort, the‘Depend­ent Variable Problem is still at the heart of important methodological debates in comparative welfare state research(see e.g. Castles 2004; Clasen and Siegel, 2007). One important outcome of these intellectual discussions in recent years is the understanding that single-epistemology approaches are less preferable than combinations of large-n quantitative and qualitative case study designs. Even within the quantitatively-informed literature, scholars have increasingly stressed the importance to account for the multidimensionality of the concept of‘welfare state change’ – in other words: single-indicator research(and we should add: sin­gle-domain research) is prone to providing simplistic and – in the worst case – mis­leading assessments of welfare reform trajectories across mature welfare states. Simultaneously, and for related reasons, the long running debate on the question of how we might accurately and meaningfully classify the diverse welfare states found across the high income countries of the OECD has become increasingly characterised by dissensus(see Abrahamson, 1999; Arts and Gelissen, 2002). For the most part scholars have agreed(albeit often implicitly) that the focus on social rights, social stratification and the welfare mix in Esping-Andersen’s Three World of Welfare Capitalism makes sense. Increasingly – however – scholars have argued ± Both authors are Lecturers in Social Policy at the University of York, United Kingdom. 27