  The role of the effective momentum approximation to disentangle Coulomb
distortion effects in quasielastic $(e,e')$ reactions is investigated. The
separation of the cross section in longitudinal and transverse components is
discussed including higher order DWBA corrections due to the focusing of the
electron waves.The experimental studies performed, in the last few years,
making use of different approximate treatments are shown to be sometime
inconsistent. As a consequence some of the longitudinal and transverse
responses, extracted from the inclusive cross sections cannot be considered
reliable. A separation procedure based on the effective momentum approximation
is discussed in connection with the recent experimental data on
electron/positron quasielastic scattering on $^{12}$C and $^{208}$Pb.
