More than a decade ago, Dr. Lawrence Rudner of the University of Maryland discovered that "in every subject and at every grade level of the ITBS [Iowa Tests of Basic Skills] and TAP [Tests of Achievement and Proficiency], home school students scored significantly higher than their public and private school counterparts." Stunningly, "by grade 8, the average home school student performs four grade levels above the national average."
But that was more than a decade ago. Comes now the most comprehensive study ever completed of homeschoolers' academic performance (PDF here).
The Home School Legal Defense Association reports that even though "the numbers and diversity of homeschoolers have grown tremendously over the past 10 years" -- the number of homeschooled students has essentially doubled -- "homeschoolers have actually increased the already sizeable gap in academic achievement between themselves and their public school counterparts -- moving from about 30 percentile points higher in the Rudner study (1998) to 37 percentile points higher in the Progress Report (2009)."
The national average for public-school students is the 50th percentile in all the standardized-achievement subtests (reading, language, math, science, and social studies). For homeschoolers the percentile scores are 89 (reading), 84 (language), 84 (math), 86 (science), and 84 (social studies).
Interestingly, the study found that homeschooled students whose parents did not have college degrees still performed at the 83rd percentile. ("When amateurs outperform professionals," Thomas Sowell once wrote, "there is something wrong with that profession.")
Moreover, the homeschooled students in the lowest income category (household income: $34,999 or less) performed at the 85th percentile.
And what did it cost to achieve these results? $9,666, perhaps? No, "the median amount spent per child each year was $400 to $599."