*ACE, the curriculum with which I am most familiar, is certainly inadequate. It consists of units on various subjects designed for student self-learning. The student reads through the material and then takes a test on that unit; answers are based on rote memorization. Then the student scores themselves using a scoring key. The curriculum also contains a lot of biblical material.
Perhaps some former homeschoolers can provide information on other curricula.
Another aspect of homeschooling quality is the level of the homeschooling parents’ knowledge and teaching skills. Often this is woefully inadequate and sometimes nonexistent. In 2016 16% of homeschooling parents had a high school or equivalency education; 15% never finished high school.
In most cases the state is unable to track or evaluate the students’ level of achievement because homeschoolers have successfully demanded little or no monitoring by the state. Therefore, many students—who are promised that the homeschooling program matches or exceeds public education—find that they must take remedial education to get into college…Fundamentalist homeschooling has a very strong anti-science bias—especially in any field related to evolution, such as archaeology, genetics, and age-dating techniques. So far as I know, all fundamentalist homeschooling embraces Young Earth Creationism, which claims that the earth is no older than 10,000 years, that humans lived with dinosaurs, and that evolution is a lie…4. Widespread Child Abuse
You probably have heard some of the horror stories of homeschooled children who have been severely abused—they seem to be far too common in the press. Not all parents are child abusers but many are, and I think there are two reasons for this connection.
First, severe child-rearing techniques are widely popular among fundamentalists. There are a number of widely distributed books that promote these principles, which many outside fundamentalism consider abusive. One principle is to ‘break the spirit’ of the child—even as an infant. Another is to use corporal punishment (hitting the child) as a primary way to form control and secure obedience.
Secondly, some parents are criminally abusive to their children in additional ways. For both groups homeschooling is a convenient way to avoid detection and possible arrest*
And this is from a Christian site that is generally in favor of homeschooling.
Poring over their stories, I was shocked to find so many tales of gross educational neglect. I don’t merely mean that they had received what I now view as an overly politicized education with huge gaps, for example, in American history, evolution or sexuality. Rather, what disturbed me were the many stories about homeschoolers who were barely literate when they graduated, or whose math and science education had never extended much past middle school.