If you look at NAEP data, students in many places -- including Maryland -- have already plateaued. Teachers don't teach to the NAEP because there is no incentive, and the results are totally anonymous, disaggregated only by state, race, and a few other broad categories. The NAEP, which I think is an extremely high-quality test, is a better measure of overall progress over time. It's not perfect, since states haven't yet agreed to common standards, but its results tell a lot more about long-term student learning than do MSA scores. Changes in MSA scores are NOT meaningless, but they don't reveal much about overall teacher quality or genuine, long-term improvements in student learning. In education, we've been working within pretty much one paradigm for a long time. What's the quotation-- "Insanity is doing the same thing over and over and expecting different results"? It's time for serious reforms.

Whether or not it exists, I think the plateau effect is a useful model. I mean, when a student gets stuck, it's a lot more encouraging to think of it as a plateau than a failure :P