It is interesting that someone would consider this a relevant point. Rightfully, teacher's salaries should be compared to the results they produce, not how their salary stacks up to other unrelated fields, other government employees.
In the private sector - an employee's worth is determined by their results. No company pays an employee more than that employees output is worth to the company (simple economics).
Granted, schools don't measure success with profitability, so we can not use that gage. What the schools are measured by is the quality of the students that are in the school system and graduating from it.
In a real world comparison, then, teacher pay should be tied to what the students have learned, how they perform on exit exams.
From the discussions I have seen on FR and the teachers posting to them, I suspect teachers do not really want to be compared to the real world. In that respect, then, the comparison you point to is relevant to the teachers, if not the rest of us.
The "real World" is that a public school district is a governmental agency, and they exist because the public wants them. As a former teacher, I do not see, for the life of me, how you can tie salary to the performance of students. Exceptions would be the scores that students get in AP courses, over a period of years, but that --to me fair--would depend on the teacher's ability to select students. I mean, to have the same choices as a football coach.
Of course it's a relevant point. The entire point of the article we're supposedly commenting on is that teachers are paid so much more than the "average workers" in their states.
From the discussions I have seen on FR and the teachers posting to them, I suspect teachers do not really want to be compared to the real world.
For many of those of us posting on FR, teaching is a second career. We know what we could and did make in "the real world" and we know what we are earning as teachers and how the working conditions compare.
We know, and knew when we became teachers, that merit has very little, if anything, to do with how much you are paid, and the only real way to get promoted in education is to leave the classroom. I know it's not likely that science and math teachers will ever get paid more than elementary and P.E. teachers, because there are more of them than there are of us - although just the law of supply & demand ought to dictate that we be paid more, you'd think.
We also know that most teachers do not work 7 or fewer hours per day for only 185 days per year, and we know what we do when we were at work -- and, believe me, if you've never taught, you may *think* you know, and you may *think* it's easy, but you don't have a clue.