In the year 1998, California began a massive experiment that focused on testing students and holding teachers and administrators accountable for results. The goal: dramatic, system-wide improvement. Schools' performance began to be measured using California's Academic Performance Index (API). In 2001, with passage of No Child Left Behind (NCLB), the focus became even sharper. NCLB required that all students be proficient in reading and math by the year 2014. "Annual Yearly Progress"--or AYP--measured schools' progress toward this ambitious goal. All subgroups of students had to make progress every year toward this goal of proficiency for all. In 2005, tests were adjusted, curricula redesigned, and accountability measures debated--but overall, the results seemed discouraging. For example, the Education Trust reported that Latino eleventh graders typically read below the level of white seventh graders. A report by California's nonpartisan Legislative Analyst estimated dropout rates in California's largest urban districts above 50%. The California State University system reports that large numbers of students who do earn a diploma still need remedial courses before they are ready for college-level studies. Yet some schools are doing better. "The California Best Practices Study" is one of the first to use California's new tests to identify the most successful high schools and then to take the crucial next step of launching an intensive investigation of what they are doing right. The study reveals a set of strategies that enable more high school students--of every ethnicity and English-language ability--to succeed. It shows--in detail--how some schools are beating the odds. This approach makes this study essential reading not only for school and district leaders, but for everyone willing to play a role in helping schools get better. The main finding is understood by every teacher and parent: what matters in schools is good teaching. However, this study goes beyond that platitude to discover how good schools and school districts go about ensuring that good teaching is the norm in every classroom for every child. California schools achieving surprising results have found and applied a few key strategies to enable teachers to do their best work. The most successful high schools serving the most challenging populations: (1) Use consistent curriculum and frequent diagnostic tests; (2) Find and adopt "best practices"; and (3) Invest in improvement. These strategies may sound simple, but they are challenging, and perhaps even revolutionary, because they call into question many commonly held beliefs about teaching and about how schools work. Appended are: (1) Tools and Artifacts; (2) Glossary; (3) Sample Sites Demographic Data; (4) Achievement Data Summaries; (5) Bibliography: For Further Reading; and (6) California Best Practice Advisory. (Contains 4 footnotes.) [This report was written with Caren Arbeit, Carla Praglin and Sune Goldsten.