In an ideal world, classes would be small, teachers would be uniformly excellent, and schools would always come under budget.
But we don’t live in an ideal world, which means we need to consider trade-offs. Since trade-offs are a condition of the human race, it’s sometimes useful to look at what people in other countries have found, especially if they share some cultural and political qualities with the U.S.
According to one researcher in Australia, “Research shows unequivocally that it is far more valuable, both in educational and fiscal terms, to have good teachers than lots of teachers.”
This is from an article in the journal Educational Research for Policy and Practice.