Let's go with $4/hr/student, which is probably very low by today's standards. And even though my contract allows me to have an average of 33 students per class, with up to 36 in any class, let's go easy and say 30 students per class.
Teaching 5 classes per day, that's 150 students, or $600/day. We have 181 days with students, for a total of $108,600. But my contract calls for 185 days per year--pay me the above, and I'll work those extra four days gratis.
But let's get back to the linked article. This author makes a common mistake:
In South Korea, for example, schools have average class sizes twice as large as the United States, 49 versus 23, but score 21 percent higher on international seventh-grade math tests.
What might help explain that unexpected result? South Korean schools draw from the top 5 percent of college graduates. American schools, by contrast, recruit their teachers, on average, from the bottom third of college students.
How do South Korean schools attract the top university students? Money. Larger class sizes frees up the resources to pay South Korean teachers much higher salaries, drawing the best and brightest into the profession. If American schools paid veteran teachers as well as South Korean schools do, teachers would average more than $116,000 in annual salary.
How is it, do you think, that South Korean teachers are able to manage a class of 49 students? I can tell you that it's not because they graduated in the top 5% of their college classes--heck, I graduated in the top 5% of my college class. What is it that's different about Korea and the US? What could it be, I wonder? What would account not only for their teachers' ability to manage classes of almost 50 students, but also for the Korean students' better academic performance when compared to Americans?
Culture. Korea has a much more homogenous culture than we do, and that culture places a higher value on education than ours does. Culture explains the achievement gap between Americans and Koreans, and also explains the achievement gap between different types of Americans. Paying teachers $116,000 isn't going to make them any more able to teach in a culture that doesn't value education much--and if you complain that your kid has too much homework that gets in the way of soccer practice, piano practice, volunteering at the soup kitchen, and taekwondo, then you're proving my point for me.
But I'll still take the money. I'm mercenary that way.