The 1.5 million number is the very same number that was given when I began homeschooling seven years ago. I would be willing to bet that this number comes from some guestimating educrat. The number may actually be much higher because there are more than 30,000 homeschooled kids in each of the 50 states (which is what would make the number 1.5 million). The true number is probably closer to 1.5 homeschooling FAMILIES. Each homeschooling mom is teaching at least 2 to 5 kids.
Something I've noticed since I began teaching my own at home is that when someone asks me where my children go to school and I say that I homeschool them, more and more people look at me, smile and say, "Good for you." It has been quite a while since I've heard the 'socialism' comment.
On second thought maybe it would be safer to keep the number at 1.5 million kids rather than families. We wouldn't want to blow there minds, just yet.