This document is intended to support a Regulatory Impact Analysis (RIA) required for a major Corrective Action regulation proposed by the U.S. Environmental Protection Agency. The objective of the RIA is to evaluate the impact of the proposed regulations on the regulated community, and determine whether the regulations will be protective of human health and the environment. The effectiveness indexing scheme described in this paper was developed to provide input data to a multi-media contaminant fate and transport model used in the RIA to assess the pollution potential of ground water, surface water and soil. Effectiveness is defined as the ability of the waste containment system to prevent the mobilization and transport of contained waste outside the system in any phase and direction. A rating (indexing) scheme has been proposed for assessing the long-term effectiveness of clay caps, synthetic caps, composite clay and synthetic caps, clayliners, synthetic liners, the Resource Conservation and Recovery Act (RCRA) Subtitle C liner systems, and vertical barrier walls. The indexing system is based on a review of literature on initial and potential performance indices of the structures mentioned.