We apply the singular value decomposition to compress the degrees of freedom of T-3 amplitude for the CCSDT-1 method (compressed CCSDT-1). This method enables us to make the number of the T-3 amplitudes less than that of the T-2 amplitudes, making CCSDT-1 calculations much less expensive without losing accuracy. We perform test calculations on some atoms and molecules to investigate the applicability of this method. Computational results for the electronic energies as well as. timings of these calculations are presented. (C)2004 American Institute of Physics.