A comparison of measured Stokes parameters and atomic collision parameters (Plin,gamma,Lperp,P+) is made for the excitation and de-excitation of the 3S-3P and 4S-3P transitions of Na respectively, for electrons with incident energies of 22, 30 and 50 eV. These parameters are obtained from `time-inverse' experiments in which electrons are either superelastically (3P-3S) or inelastically (3P-4S) scattered from the laser prepared 3P state. The data are compared with calculations from a convergent close coupling (CCC) model and a second-order distorted wave Born (DWB2) model. Both models demonstrate very good agreement for 3S-3P transitions. For the 4S-3P transitions, the DWB2 is in better accord with experiment than the CCC for the Plin parameter, the CCC is in excellent agreement with experiment for gamma and Lperp, and neither is in accord with experiment for P+.