Pretty sure this is the SEH effect. The first of a large block of kids from SEH are starting to hit that school. Many are from minority families but there isnt that much diversity as they are socioeconomically very homogenous regardless of ethnicity. Then you factor in that many of the truly economically disadvantaged kids were shifted over to the new high school north of 78. Lastly they are likely viewing rapidly improving academic perferormance over the last decade that is more attributable to the shift in mix of students rather than the improvement per se of specific populations.
Dont get me wrong. Its a GREAT story but I suspect the story is less of an actual improvement in the school system itself and more of the City of SM remaking itself very successfully as an upper middle class community by attracting well planned development in far flung areas supported by MR fees. Sometimes it works!