AbstractThe effects of anisotropic scattering approximations in the monoenergetic transport equation are evaluated by calculating discrete eigenvalues, fluxes due to a plane source, and slab critical half-thicknesses, all for homogeneous media. Relative toP2scattering approximation results, which are deemed accurate because of their agreement withP4solutions, the simple transport approximation overestimates eigenvalues and underestimates half-thicknesses in multiplying media while aP1scattering approximation underestimates eigenvalues and overestimates thicknesses, but with smaller error. In the plane source problem, where the detailed flux behavior is observed, the transport approximation is even less accurate; but an extended transport approximation is found to be much more adequate. In overall effectiveness, in order of increasing accuracy, the approximations considered are ranked as follows: 1) transport, 2) forward-backward, 3) first-order Legendre, 4) extended transport, and 5) higher order Legendre. Some evidence is given to indicate that, even for severely anisotropic scattering, relatively low-order Legendre approximations are sufficient to include anisotropic scattering effects.