The problem with this article is that the author keeps talking about aggregate "achievement". Is it better to slightly improve the aggregate number of children

The problem with this article is that the author keeps talking about aggregate "achievement". Is it better to slightly improve the aggregate number of children who can limp across the arbitrary "achievement" thresholds supposedly measured by ever-changing tests, or make sure that the resources exist for every child to exist in an environment that allows them to learn at their own speed? Classrooms forced to teach at a pace that accommodates the slowest learners necessarily hold back the education and growth of every student capable and eager to learn at a higher rate (as well as inducing boredom and apathy). I'd argue that we should be increasing resources to the slowest students who have the hardest problem closing the achievement gap rather than trying to eliminate that gap by pretending that all students learn at the same rate and holding back our best and brightest.