More comments on backfilling from Jeanne Allen from The Center for Education Reform:
Regarding the backfill debate, it's amazing that this point is only now being surfaced by Mike, when some of us have been making the argument for years that too many who operate in the charter sector make unfair comparisons year after year — and demand policy changes based on such inaccurate comparisons. I wish he would have spent more time on the issue of schools choosing NOT to enroll - which he calls backfill - after a fixed point in time. They are able to demonstrate much higher test scores than those which remain the same in composition. I have seen it hundreds of times — the schools that start in a community, by community people, would never dream of leaving Johnny at the door when a spot opens up. Conversely, most widely acclaimed CMOs make it clear that no one need apply after the first grades are assembled. It's not a bad model — just a different one.
One of the most pervasive, pig-headed problems of the charter movement is when advocates make apples to oranges comparisons between schools which stop enrolling after the first kids start (eg KIPP) [Whitney's comment: KIPP NY backfills in every grade through 10th] vs. those who take all comers all the time (e.g., most independent charters which CMOs often criticize for failing to achieve aggregated, higher test scores). I admire those which take a 5th grader or 10th grader mid-year and resolve to serve that student and raise their achievement, even if their bottom line might reflect poorly as a result of students who came late but were still tested on time regardless. Most parents know what's happening among these different actors, but the schools fail to acknowledge it publicly even when boasting of great success, so kudos to those who are raising the red flag.
Such posturing has created a rift among charter schools in cities like Washington, DC, where schools which choose not to disrupt their original student body often out-perform those that put mission and opportunity above their bottom line, though the differences are small. It would be great to see what would happen if some schools that don't enroll after day 1 start doing so— would their great model still be great? How would their educators fare? What would the comparisons look like then? Inquiring minds want to know.