Commensuration and proliferation: similarity and divergence in law’s shaping of medical technology

The concept of commensuration - 'making things the same' - is receiving increased attention in studies of fields of social practice such as climate regimes, accounting and medical error reporting. The part played by analogy in common law is well known, but the way cognate processes work through regulatory institutions and regimes (ie commensuration) is less recognised. Connected to commensuration and arising from it, one can propose a concept of 'proliferation' to capture instances of enactment of law (institutional design, development and practices) where commensuration is not possible or attempted, or where it is challenged in some way. This paper will explore and review recent more or less explicit developments of the concept of commensuration, propose the related concept of institutional proliferation, and explore the application of these to recent developments in the European Medicines Agency (EMA). The focus will be on EMA's implementation of the EU's Advanced Therapy Medicinal Products Regulation, how 'combination products' (medicine/device combinations) are being managed in that evolving regime, on EMA's design of a number of innovative institutional forums for stakeholder inclusion and linkages to scientific societies (proliferation), and its recent involvement in proposals for a 'recast' of medical device regulation.