the best outcome is when a group of stay at home parents form a group, and in turn teach their specialties... shuttle kids between them... one English (language arts), then math, science, social studies...etc... as commented, some of the religion based programs have a canned curriculum..

additionally there are charter schools that receive funds from the school district (in Florida there is a rather complex formula, but around $6000 per student)... the charter schools go through an evaluation by the home district for approval...

I was a 30 year public high school teacher, and was not impressed with any home school program... it is pretty hard to justify a $600 microscope, $100 electrophoresis gel, $1500 analytical balance, not to mention a relatively cheap $125 triple beam balance and glass ware...