I'm personally not convinced that the test score comparisons between homeschooled kinds and children in the public education system is really an apples-to-apples comparison; after all, the act of homeschooling your children demonstrates a greater involvement in your child's education than the average parent of a child in the public education system.
With that said, even though I graduated from one of the best public education systems in the world I'm not convinced that public education is scratching the surface of the average child's potential. From what I have seen the public education system is set up so that 75% or 80% of students will be able to obtain satisfactory grades with almost no effort from the student, teacher or the student's parents; and the bottom 20% to 25% are allowed to "fail" because no one is willing to put in the effort to evaluate these children for learning disabilities, question the effectiveness of the curriculum or the teacher, or try to motivate these children to obtain more. While I could be wrong but I suspect, if you were able to make enough changes to have children being educated at close to their potential, most children could become competent at a grade 12 level in most subjects by the time they graduated grade 8 or 9.
