The ionospheric height-integrated Hall conductivity has been derived from two different techniques: first, by combining ground-based magnetometer observations with measurements of the ionospheric electric field made by the Scandinavian Twin Auroral Radar Experiment (STARE), a coherent radar system, and, second, by combining electron density measurements made by the European incoherent scatter radar (EISCAT) with a neutral atmosphere model. For the events analyzed, EISCAT did not operate in a mode that allowed the electron and ion temperatures to be measured below 131 km. In the analysis these temperatures are therefore assumed to be of the same magnitude. For small electric fields (25 mV/m) we find the two conductivity estimates to be in good agreement. However, for large fields (75 mV/m) the former method yeilds a conductivity value larger by a factor of 1.5 than the latter method. We interpret this result as being due to an increase of the electron temperature above the ion temperature, possibly associated with the excitation of unstable short-scale plasma waves in the ionospheric E region. The combination of STARE and magnetometer data is demonstrated to lead to realistic estimates of the Hall conductivity in the eastward electrojet. ¿ American Geophysical Union 1988