Much media coverage was given to the U.S. Department of Education’s recent numbers (provided by the National Center for Education Statistics) showing that 1.5 million students are homeschooled in the U.S.

However, many are wondering just how accurate those numbers really are. Homeschool advocates believe that number is too low. Here’s why.

“We have an ongoing dispute with the Department of Education over the numbers,” said Ian Slatter, director of media relations for the Purcellville, Va.-based Home School Legal Defense Association, an 85,000-member organization that supports the legal rights of homeschooling families.

According to Slatter, states such as California, Illinois, Florida, Wisconsin, and others, are “private school states,” meaning that if a parent home-educates, they’re technically considered a private school.

“When the government surveys the population via telephone, there are some parents who will give the technically correct answer that they use a “private school,” rather than telling the government that they homeschool,” described Slatter. Slatter believes that the actual total number of families homeschooling full-time is 2 million.

Mark Hegener, publisher of Home Education magazine, also disagrees with the overall numbers.

“Are people answering the survey questions technically correct, or in such a way because they don’t trust data-takers?” asked Hegener. “More people are taking diverse public school options, such as virtual schools, than homeschooling,” he said, wondering how it’s possible for the Department of Education to obtain accurate information.

“The questionnaire would not have made sense to homeschooling parents who reported that their child was in a private school,” responded Jo Ann Webb, spokeswoman with the Department of Education. “They would have been asked a long series of questions about the characteristics of the private school and finally the name and location of that school. Operationally, we linked the school reported during the interview with our census of private school data set.”

Government numbers do, however, support a larger number when considering students who are homeschooled even part-time. Taking into consideration children whose parents choose homeschooling for at least part of their education, the number of students homeschooled at least part-time is 1.5 million, making the total number of students who are homeschooled in the U.S., either full- or part-time more than 3 million.