This report presents the results of the professional judgment component of a seven month project undertaken by American Institutes for Research (AIR) to answer the following question: What is the cost of providing all California public school students with access to the California content standards, thereby achieving appropriate levels of proficiency standards established by the California Department of Education? The discussion in the report summarizes the major elements of a "costing out" study. "Costing out" is a term regularly applied to this type of analysis of adequacy in education. In the course of this endeavor, AIR obtained input from professional educators and convened a three-day meeting with highly-qualified California educators to estimate the cost of an "adequate" education. Excluding debt service, public schools in California spent about $45.29 billion in 2004-05 to educate its students. The main results of this study suggest that an additional $24.14 to $32.01 billion would have been necessary in this same school year to ensure the opportunity for all students to meet "academically rigorous content standards and performance standards in all major subject areas." The following are appended: (1) Background Information on Goals Statement; (2) Professional Judgment Panel Instructions; (3) Program Design Documents; (4) Professional Judgment Panel Information; (5) Blue Panel and Gold Panel Program Design Documents; (6) Suggested Reading for Professional Judgment Panelists; and (7) Descriptive Statistics. (Contains 31 exhibits and 56 footnotes.) [This research was conducted at the request of the Governor's Committee on Educational Excellence, the California Superintendent of Public Instruction, and members of the California Legislature. The report was completed with the assistance of Tom Parrish, Jenifer Harr, Maria Perez, and Paul Gubbins.]