Dear Mr Patrinos,
I have one doubt. Box I.2.2 In the PISA 2012 report Vol I (pp 52-43), explains that trend information can be computed using the first year when a given subject area was prioritised in the test as the reference scale. Thus, trends can be computed for the period 2000-2012 in Reading, 2003-2012 in Math, and 2006-2012 in Science. If I understand correctly, this basically means that for Math and Science scores in 2000 and 2003 for Science) to be considered comparable to the rest of the series, they would need to be re-scaled; that is, we should not use the original data directly.
I got the impression your post relies on the original 2000 (and 2003 for Science) scores without any re-scaling. Is that impression correct?
If this is the case, would you be so kind to explain to what extent the description of progress levels depicted by your text are reliable? As you can imagine this issue is particularly sensitive for a citizen of the country (Peru) your post identifies as the one that improved the most between 2000 and 2012 in Reading and Math and showed also an important progress in Science. While this is clearly correct in Reading, since Peru did not participate in PISA 2003 and 2006, I wonder how reliable that assertion is regarding Math and Science.