Since the 2001 passage of the No Child Left Behind Act (NCLB), test-based accountability has been an organizing principle--perhaps "the" organizing principle--of efforts to improve American schools. But lately, accountability has been under fire from many critics, including Common Core opponents and those calling for more multifaceted…

In just the last ten years, goaded by broad and still unsettled cultural shifts, education practices have changed dramatically. Schools are no longer just recording and analyzing inputs--dollars spent, number of days of instruction, numbers of students per teacher--but pushing their data-gathering and analysis efforts into the brave new world of…