We prove the effective Hall factor inp-GaAs to be larger than values discussed in the literature up to now. The scattering rates for the relevant scattering mechanisms inp-GaAs have been recalculated after critical testing the existing models. These calculations allow to deduce theoretical drift and theoretical Hall mobilities as functions of temperature which can be compared with measured data. Theoretical Hall factors in the heavy and light hole bands and an effective Hall factor result. The calculated room temperature values of the drift mobility and of the effective Hall factor are118 cm2/V sand 3.6, respectively. The fitted acoustic deformation potentialE1=7.9 eVand the fitted optical coupling constantDK=1.24×1011 eV/mare close to values published before. It is shown that the measured strong dependence of the Hall mobility on the Hall concentration is not mainly caused by scattering by ionized impurities but by the dependence of the effective Hall factor on the hole concentration. ©1997 American Institute of Physics.