Recent efforts in estimating the global distribution of the electric potential as well as of ionospheric and field-aligned currents on the basis of ground magnetic records are reevaluated. For this purpose, we have repeated crucial tests for the algorithms by using a data base from the IMS Alaska chain of magnetic observatories along with completely different ionospheric conductivity models. It is found that the ionospheric current patterns are only weakly dependent on the choice of the conductivity, while the calculated field-aligned currents are somewhat more sensitive and the electric field is quite sensitive to the assumed conductivity, as expected. A test is also conducted by using the calculated field-aligned currents as inputs to an inverse calculation to attempt to reproduce the original ground magnetic perturbations. The results were quite satisfactory, indicating that the numerical accuracy of the algorithms is adequate. These tests increase our confidence that ground magnetic records from a close network can be used to study the extent to which the magnetosphere and ionosphere are electrically coupled.