The Clayton Christiansen Institute maintains a database of more than 400 schools across the United States that have implemented some form of blended learning, which combines online learning with brick-and-mortar classrooms. Data the Institute has collected over the past six months suggests three trends as this model continues to evolve and mature. In this article, Michael B. Horn and Julia Freeland Fisher describe schools that illustrate each of these trends. Some schools are using Station Rotation to differentiate instruction within the structure of the traditional classroom. Others are taking innovation one step further and finding ways to use time more flexibly. Still other schools are disrupting traditional structures entirely by upending seat time and giving students control over their learning. The authors concluded that "blended learning is still in flux, in the best sense of the word."