@DrewDad,
That's not the relevant test, for several reasons.
1) I shouldn't ask littlek, I should ask her students -- preferably students who can make a "before" and "after" comparison.
2) I shouldn't just ask if her training is worth
something. I should ask --
a) how much more it is worth than getting on the job two years earlier, and having two more years of on-the-job experience -- which would have been her alternative in Texas.
b) how her extra qualification compares to her increase in salary. From the taxpayers' point of view, one advantage of less qualified teachers is that they're cheaper, so their tax dollars can hire more of them -- which may or may not a good tradeoff.
3) One major promise of a free-ish market in schooling is that it makes it easier to experiment with radically different pedagogical approaches to schooling. By contrast, government licenses for teachers inevitably tend to enshrine the pedagogic presumtions of public schools, where the licensed teachers are expected to teach in. Hence, even if a license certifies qualifications that are valuable in a typical public school, it isn't clear at all that they are worth much in a school modeled on, say, Summerfield or Sudbury Valley. (Which happens to be my favorite pet model of schooling.)