The intensity asymmetry of the secondary emission spectra of thin iron films on W(110) excited by spin-polarized electrons was measured at various geometrical arrangements and various primary energies. The magnitude and shape of the Stoner excitation asymmetry provide information on the magnetic state of the film. The geometrical structure of the film influences its magnetism and this is reflected in the asymmetry of the spin polarized electron energy loss spectra (SPEELS). Oxygen adsorption reduces the asymmetry of Stoner excitations, but not as dramatically as in studies of Ni surface. The kinematics of the scattering process influences the asymmetry of the spectra and should be taken into account while using SPEELS for studying surface magnetism. Theoretical analysis of asymmetry spectra measured at various scattering conditions is required. © 2013 Elsevier B.V.