A patchwork of state standards is failing to produce high school graduates who are prepared either for college or for work, three education policy organizations say in a new report. The solution, they say, is to adopt rigorous national standards that will turn the high school diploma into a "common national currency." "For too many graduates, the American high school diploma signifies only a broken promise," the groups, which favor standardized testing to improve education, say. Working through what they call the American Diploma Project, the organizations — Achieve Inc., the Education Trust and the Thomas B. Fordham Foundation —...