The application of rotational echo double resonance REDOR nuclear magnetic resonance NMR for accurate distance measurements has thus far been largely restricted to isolated heteronuclear two-spin systems. In the present paper, the informational content of REDOR curves is explored for systems characterized by multi-spin interactions. To this end, numerical REDOR simulations are presented for cases in which single observe spins S are dipolarly coupled to groups of spins I in distinct geometries. To develop the utility of REDOR for characterizing dipolar couplings in unknown andror ill-defined geometries, the validity ranges and systematic errors of certain analytical approximations are studied. In the limit D S of short dipolar evolution times where 0 F F0.2 to 0.3, the REDOR difference signal intensity increases approximately S 0 proportional to the square of the dipolar evolution time. Here, the curvature depends simply on the second moment M 2 characterizing the overall strength of the heterodipolar coupling, irrespective of specific molecular geometries. Fitting experimental REDOR data in this manner produces slight systematic underestimates of M . However, these errors tend to be 2 counterbalanced by additional systematic errors made by neglecting weak couplings to more remote spins and distribution effects caused by disorder. Based on these findings, the results suggest a convenient method of obtaining site-resolved second moment information in disordered materials.