This report details the Annie E. Casey Foundation's four-year effort to develop a "results-based accountability" (RBA) approach to its K-12 education portfolio. Though still a work in progress, the Foundation's experience with RBA can help other philanthropic organizations and individual donors develop their own approaches to producing and documenting the results of their investments. It can also assist Foundation grantees in their quest to clarify and communicate more clearly to donors and other interested parties the results they want to achieve and their progress in achieving them. Appended are: (1) The Annie E. Casey Foundation's 2004 Education Investments; and (2) Education Partnerships by Type of Program Support. (Contains 24 figures and 19 endnotes.) [This publication was written with assistance from Bryan C. Hassel and Amy Way.]