Impact Assessments (IA) are a key element in the development of policy proposals by the European Commission (EC). They provide evidence for political decision makers on the advantages and disadvantages of possible policy options by assessing their potential impacts. This evidence should be quantified whenever possible, and hence it is of interest to examine to what extent models have been used in IAs. The purpose of this report is to understand how the EC is positioned with respect to external providers as regards modelling contributions to IAs, as well to provide an input into potential future development of the Commission's model portfolio. The results of a statistical analysis for the period 2009-2014 shows that 16 % of the published 512 IAs used models or were predominantly model-based. In terms of absolute numbers, Directorate Generals (DGs) CLIMA, ENER, ENV and MOVE account for more than half (51) of the 91 model-based IAs. Within the model-based IAs, 52% used results exclusively or partially provided by external contractors, while 48% used models run in-house by DG JRC. The Commission uses a wide range of models (91 for the IAs during 2009-2014), roughly 60% of which were used only once. The 24 most frequently-used models represent 70% of all cases in which modelling were used for an IA. Notably 11 of them account for roughly 48%, almost all being run by contractors, mostly in tandem for energy-transport-climate policy scenarios. The most frequently-used model is PRIMES, used in 28 out of 263 cases (11% of the cases), followed by 10 other models which are used exclusively or predominantly with PRIMES in the context of the energy-climate scenarios (GEM-E3, TREMOVE, CAPRI, POLES, G4M, GAINS, GLOBIOM, LUISA, PROMETHEUS and TRANSTOOLS). Frequently-used models for the economic and monetary union are the in-house models QUEST and SYMBOL. The most frequently-used models of DG JRC number about 10 which have been used in 46 cases; these are energy models (GEM-E3 and POLES), followed by environmental models (the LUISA modelling platform and LISFLOOD), the micro-economic model for financial markets SYMBOL, the transport model TRANSTOOLS and the agricultural models belonging to the iMAP platform - CAPRI and AGLINK-COSIMO.
