For years California has been a leader in public education. In 1999, the state implemented some of the strongest content standards in the country through its main accountability metric, the Academic Performance Index (API). The state has also signed onto the Common Core State Standards, taking important steps to ensure its students are college- and career-ready. But California faces big challenges. There is growing agreement that the API doesn't work as well as it should. Relying too heavily on low-level standardized tests, it has become more an indicator of students' wealth than of a school's educational quality. This shortcoming has left too many students unprepared for college work. Yet there is little agreement over what should replace the API. This paper argues that California and many other states have the foundations in place to build better accountability systems--systems that actually focus on meaningful school improvement; they just need to put the pieces together in the right way. Drawing lessons from previous Education Sector reports, the author proposes a three-pronged approach to putting California back on a path to national leadership in education. These are: (1) Measure a school's performance based on indicators of success, like graduation rates, college enrollment, remediation, and degree or certificate completion, rather than proxy measures, like standardized test scores; (2) Better analyze performance data. For example, rather than comparing a school's performance to an overall benchmark score, look at the school's individual progress year to year to see where exactly it is making gains and where it's not; and (3) Send highly trained, independent consultants to schools to review, observe, and judge performance. A borrowed idea from England's inspectorate model, these tailored visits will allow for more directive, personalized feedback that will better drive improvement efforts. (Contains 2 figures and 15 notes.)