This seems like they walked in looking for proof of their already established conclusion. If you look at Finland, Australia, Korea, Japan and New Zealand you see a cluster of countries who are paying their teachers well and who aren't getting results (Edit: By this I mean the countries below them aren't getting results yet are paying the same amount). Compare Denmark to Finland or Spain to New Zealand and then explain to me how the authors' thesis rings true.

Plus we have anecdotal evidence that contradicts their conclusion in the U.S: Individual State salaries vary pretty significantly ($37,000 to $59,000) yet education results don't seem to reflect those salaries

Teacher Salary By State: http://www.teacherportal.com/teacher-salaries-by-state

State Education Rankings: http://www.vermontbiz.com/news/september/state-education-ran...

I don't entirely disagree with the thesis that making "teacher" a more revered position will draw better people to it. But there are clearly other factors at play that the authors chose to disregard because they wanted to prove their already established conclusion.

(If it were me I'd be comparing Switzerland, Germany and Sweden and trying to figure what the differences are there)