The purpose of the symposium was to provide an assessment of our current quantitative understanding of magnetospheric processes. The ‘quantitative’ test is met when a model (usually computer code) output is in good numerical agreement with the observational data collected for a particular magnetospheric feature. The ‘understanding’ test is satisfied when the physics of the particular feature is understood and used to construct the model. Currently the quantitative models used are mostly representative (as opposed to explanatory). Thus, although there may be quantitative agreement between the model output and observational data, it can still not be said that the particular process or feature in the magnetosphere is quantitatively well understood. Very few quantitative explanatory models are in existence (even the models of the magnetospheric magnetic field are not derived from the plasma properties which produce the magnetic current systems).