Even if one thought about going to an expert on math education, where would you find one and how would you recognize one if they were pointed out to you.
From what I have read about education theory in the last fifteen years the field is full of charlatans, posers and con artist.
Whole Language and New Math are just two examples of what I mean.
For math, one goes to the faculty at Mason or VA Tech.
Whole Language is in the past for VA, at least as long as UVA is providing funding and coordinating Federal grants.
If a school wants to evaluate a book on the cheap, they ask the faculty who have recently obtained masters from those programs. What a county or district should NOT do, is ignore the input from their teachers and rely on book distributors and sellers for information about what the school needs.