Coastal Louisiana⁰́₉s built and natural environment faces risks from catastrophic tropical storms. Concurrently, the region is experiencing a dramatic conversion of coastal land and associated habitats to open water and a loss of important services provided by such ecosystems. Louisiana⁰́₉s Coastal Protection and Restoration Authority (CPRA) engaged in a detailed modeling, simulation, and analysis exercise, the results of which informed Louisiana⁰́₉s Comprehensive Master Plan for a Sustainable Coast. The Master Plan defines a set of coastal risk-reduction and restoration projects to be implemented in the coming decades to reduce hurricane flood risk to coastal communities and restore the Louisiana coast. Risk-reduction and restoration projects were selected to provide the greatest level of risk-reduction and land-building benefits under a given budget constraint while being consistent with other objectives and principles of the Master Plan. A RAND project team, with the guidance of CPRA and other members of the Master Plan Delivery Team, developed a computer-based decision-support tool, called the CPRA Planning Tool. The Planning Tool provided technical analysis that supported the development of the Master Plan through CPRA and community-based deliberations. This document seeks to provide an accessible technical description of the Planning Tool and associated analyses used to develop the Master Plan.