Excitation of the 3 ³D state of helium by electrons with an energy of 370 meV above threshold is studied experimentally using the electron-photon polarization correlation method and theoretically using the convergent close-coupling (CCC) and R-matrix with pseudo-states (RMPS) methods. Stokes parameters and associated coherence parameters are presented. Despite difficulties associated with a sharp resonance in the cross section at this energy, generally good agreement is obtained between experiment and the calculations. At small scattering angles the results show a violation of the propensity rule for angular momentum transfer. CCC and RMPS calculations have also been performed at 22 and 24 eV for the 2 ¹P state and are compared with earlier angular correlation data.