Averages don't reveal how well schools do by their weakest students--the ones mastery learning is designed to help. For that, a better measure is the percentage whose knowledge is rated as "proficient" or "advanced" on the MME. In 2011, Huron had the lowest percentage of students achieving proficiency in all five subject areas; Pioneer had the highest percentage achieving proficiency in two areas, and Skyline in three. Most of the differences between Pioneer and Skyline were small--one or two percentage points--except for math, where Pioneer led Skyline by six points and Huron by eight.
In the end, Neaton says, "I would say we are all comparable. They're all Ann Arbor kids." He feels good, with Skyline's first graduating class, to have landed in the middle.
Jackson says she's concerned that people might look at those numbers and assume, "OK, Skyline is a better school than Huron, but not as good as Pioneer"--without looking at the demographic makeup of the three schools' student bodies and how that might affect the results. At Skyline, she says, "We seriously disaggregated that data to drill down to ... where were our strengths, and where were our children weak consistently? Where were my lowest-achieving kids? My highest-achieving kids--where were they weak?" They're using that information, she says, to tweak the curriculum and teaching methods.