One hundred schools in New York City are experimenting with new curriculum standards known as Common Core. In the U.S., 42 states, the District of Columbia, and the Virgin Islands have signed on to the new standards, an ambitious set of goals that go beyond reading lists and math formulas to try to raise the bar not only on what students in every grade are expected to learn, but also on how teachers are expected to teach.  The standards, to go into effect in 2014, will replace a hodgepodge of state guidelines that have become the Achilles’ heel of the No Child Left Behind law. Many states lowered standards in a push to meet the law’s requirement that all students reach grade level, as measured by each state, in English and math. President Obama has expressed a desire to rewrite the law, and many experts predict the Common Core will be a centerpiece of the effort.The new standards give specific goals that, by the end of the 12th grade, should prepare students for college work. Book reports will ask students to analyze, not summarize. Presentations will be graded partly on how persuasively students express their ideas. History papers will require reading from multiple sources; the goal is to get students to see how beliefs and biases can influence the way different people describe the same events.