Equations for a few-group model applicable to transient analysis are derived from a variational principle made stationary by the continuous-energy P1, equations. Flux-adjoint (bilin-early) weighted few-group parameters result. These can be reduced to the regular flux-spectrum weighted parameters by taking the adjoint spectrum to be constant in energy. Numerical comparisons with multigroup results show that both regular and bilinearly weighted two-group models provide acceptably accurate predictions of transient behavior when realistic pressurized water reactor cases are examined. Although there are still some theoretical questions to be examined, there appears at present to be no reason to employ bilinearly weighted parameters for either static or transient analysis.