The efficiency of selective and nonselective cross polarization in homo- and heteronuclear liquid-state nuclear magnetic resonance spectroscopy is investigated. A general classification scheme for TOCSY (total correlation spectroscopy) and TACSY (tailored correlation spectroscopy) experiments is introduced based on characteristic effective zero-quantum coupling tensors. The efficiency of polarization transfer with respect to transfer amplitude and transfer time is quantified and presented in the form of maps as a function of the relative coupling constants in systems consisting of three coupled spins. Characteristic differences in the polarization-transfer efficiency of TOCSY and TACSY variants are revealed and analyzed. Significant implications of these results are discussed for spin systems of practical interest.