https://www.understood.org/en/articles/retention-why-kids-are-held-back

https://naspcenter.org/parents/nclb_ho/

Promotion or retention: Some states or districts may determine that students who fail one or more standards tests will be retained in grade for the next year. For example, recently the state of Florida announced that over 40,000 third graders would be retained based on their failure to pass the third grade test. Other states might require summer school for students who fail to meet a criterion score on one or more of the state tests. And other states and districts may not use standards tests at all for the purpose of making promotion decisions. Because research demonstrates that retention is not an effective practice, states and districts are encouraged to base promotion decisions on more comprehensive information than standards tests alone. Knowing that a test will be used to determine promotion to the next grade places a high degree of stress on students, teachers, and parents; stress by itself can negatively affect a student?s performance on these tests!

NCLB Left so many kids behind.

Nation At Risk was horrible for the nation. https://www.npr.org/sections/ed/2018/04/29/604986823/what-a-nation-at-risk-got-wrong-and-right-about-u-s-schools

America has never had great schools (or environment) for poor people.