Standards-based has been at the heart of state and federal education policy for more than two decades. But what do we really know about the implementation of standards in the classroom? What are the methodological questions in validly measuring standards implementation? What are the key implementation questions with respect to new "college and career-ready standards"? This presentation reviews a series of studies documenting standards implementation in the No Child Left Behind era and identifies some of the most important issues for studying implementation moving forward.