The goal of this study was to determine the level of educational expenditure necessary to make ample provision for the education of all students, providing all students with the skills to meet long-term academic standards, pursue additional learning beyond high school, and become productive citizens and contributing members of society. This study drew from four established adequacy funding methodologies to estimate an adequate expenditure level. These were the successful schools method, the evidence-based method, the professional judgment method, and the cost function method. The evidence-based and professional judgment methods yielded a set of changes to the baseline prototypes necessary for Washington schools to achieve goals set at the local, state, and federal levels, and to do so with an increasingly challenging student population. The major interventions are similar, but not identical, at all three levels. The interventions are specifically adapted to the needs and structures of each level. In addition, some interventions are specific to a particular grade level. All of the interventions at each level were identified through the evidence-based method and endorsed by the professional judgment panelists. A bibliography is included. (Contains 17 figures and 25 tables.)