The two-group neutron diffusion equations have been applied to multiregion reactors to obtain the transfer function for an arbitrarily located, localized oscillatory absorber and an arbitrarily located point of observation. Results obtained from a digital computer program written for the case of symmetrical slab geometry extend previous work on space-dependent zero-power transfer functions, and establish criteria for calibrating reactor control rods by oscillation. Simple physical models suggested to explain the space-dependent effects are intuitively satisfying, agree with the computed results, and are expressed in terms that permit general application. One model describes special high-frequency behavior of the phase angle of the transfer function; another model describes the exaggerated space-dependent effects observed previously in rod calibration by oscillation.