We report results of direct measurements of the reduced Stokes parameters \skew{-1}\bar{P_1}, \bar{P_2} and \skew{-1}\bar{P_3} for electron impact excitation of H(2p) at 54.4 eV over the scattering range 10–40°. These three parameters have been measured simultaneously for the first time using a VUV double-rotation polarization analyser consisting of a MgF2 retarder followed by a SiO2 reflection linear polarizer. As expected, our measurements for \skew{-1}\bar{P_1} and \bar{P_2} are in good agreement with theoretical calculations and previous experimental data. Our data for \skew{-1}\bar{P_3} differ significantly from previous experimental measurements and theoretical calculations. Consequently, we find that the coherence parameter P+ deviates significantly from unity at 30°. If correct, this signifies that spin-exchange scattering may be more important than has previously been thought.