It has been reported that several distinct flow patterns may result when two immiscible liquids undergo Taylor vortex flow in the annular gap between a fixed outer cylinder and a rotating concentric inner cylinder. One such flow pattern (banded flow) apparently arises when less dense disperse phase droplets migrate to Taylor vortex cores duc to the centrifugal force associated with the rotation of the vortices. Using the hypothesis that centrifungally driven droplet migration to vortex cores competes with turbulent diffusion, a simple criterion for predicting when banded flow patterns arise shows consistency with numerical simulations and experiments.