  We compute scattering rates for electrons in the two-dimensional Hubbard
model for a one-orbital metal and a two-orbital band insulator by means of the
Boltzmann scattering equation (BSE) and dynamical mean-field theory (DMFT). As
an intermediate method between both, we also consider the BSE without momentum
conservation. In the weak interaction regime and for the band insulator, the
last two agree to very good accuracy. The BSE with momentum conservation, on
the other hand, shows slightly larger scattering rates, and a momentum
differentiation of these on the Fermi surface. For the Mott insulator at strong
interaction, the DMFT electron scattering rates are much larger and defy a BSE
description. Noteworthy, the scattering rates for the band insulator are
exceedingly small because -- in contrast to the Mott insulator -- there is
virtually no impact ionization.
