The dependent variable (CNT_EP_STORGRID) represents the number of patent applications deposited at the European Patent Office, classified by inventor country7 and priority year8. The data source is PATSTAT as discussed above.) This variable is constructed in a manner analogous to the dependent variable (a count of patent families by inventor country and priority year) with the difference that all types of technologies (not only storage and grid mgmt) are covered.9 Ideally, we would estimate the model using a two-stage procedure where total patenting activity is first estimated.