My daughter went to an Expeditionary Learning school in middle school. It was a K-12 school, and the math for high school was an integrated math program. The math teacher was involved in developing the particular program they used. Kids from this school did go to Colorado School of Mines and other engineering programs, and the program did work for some kids. It did not work for all kids.
However, the math teacher’s own kids went to this school for k-8 and then went to the Jesuit high school because, when push came to shove, he wanted a much more traditional education for his own kids. (who were pretty good students).