We report measurements of controlled implosion performance degradation arising from the Rayleigh-Taylor instability in inertial confinement fusion capsules. Using plastic capsules driven indirectly by the Nova laser, we studied the variation in implosion performance as a function of outer surface perturbation. Variations in both capsule x-ray and neutron emission are seen which are consistent with a model which describes mixing pusher material into fuel material. The model combines representative capsule surface characterization, implosion stability, and perturbation growth saturation.