Tuesday in Wisconsin, the newest K-12 school report cards were released. With student growth now measured, the report card results are astonishing, perhaps unprecedented, for school choice and require the attention of the education reform community.

Ask any teacher, and she will tell you that not all of her students enter the classroom on the first day of school at exactly the same level of knowledge. Some students will be ahead of the proverbial curve, and some students, unfortunately, will be behind it. This reality is problematic when one attempts to compare the performance of schools and school districts to each other. It is somewhat unfair, for example, to expect the same level of achievement from a school with many students who are two years behind academically to schools where students are more on track. Traditionally, however, this is exactly how schools have been judged—by a set level of achievement for which all students are judged to be failing or succeeding.