The 'welfare modelling business' has become central to comparative social policy in recent years. However, we argue that one important element in this literature, the usefulness of identifying 'ideal types' of welfare production that support theoretical development, has been neglected. While much effort has been devoted to the results of the number and composition of the worlds, insufficient attention has been paid to the analytical basis of welfare regimes. This article attempts an audit of the 'welfare modelling business', with a review and consideration of the main concepts used in the literature. Our main conclusion is that definitions, concepts and methods need to be given urgent priority for the investment in the business to produce future returns.