January 16, 2014 by Steve Kolowich

We know that online education went mainstream years ago. Academic leaders believe it will become even more prevalent in the coming years. But how many American students are taking at least one online course right now?

The answer, according to the latest figures from the Babson Survey Research Group, is about 7.1 million.

Or is it?

For the last decade, researchers and journalists have relied on the Babson group and its annual survey to measure the scale and growth of online higher education in the United States. With backing from the Sloan Consortium and others, the Babson surveyors have been taking the temperature of online education in the United States since 2002, when they estimated that 1.6 million students were taking at least one online course.

In those days, the Education Department was not collecting data on online higher education. “There was no interest,” according to Jeff Seaman, co-director of the Babson group. Mr. Seaman says he tried, without success, to persuade department officials at the time to make colleges and universities report their online enrollment data.

So, for the next decade, that job fell to Mr. Seaman and I. Elaine Allen, a professor of statistics and entrepreneurship at Babson College, in Massachusetts. The husband-and-wife team would extrapolate ballpark figures on online students by asking academic leaders at as many institutions as they could.

Then, in 2012, the Education Department finally started asking colleges and universities to report data on their distance-education offerings. The National Center for Education statistics has since released its own online-enrollment figures for that year (it has not yet compiled its 2013 figures).

In 2012, according to the department, 5.5 million students took at least one online course. That is 1.2 million fewer than the Babson Survey Research Group estimated that year, as several observers have noted.

So which number is correct?

The lower one, probably. The Education Department data are more likely to be accurate, “given that they are working from the universe of all schools,” says Mr. Seaman by email.

He cites a few possible reasons for the discrepancy. The Babson group and the Education Department are using slightly different definitions of distance-education courses, for one.

But Mr. Seaman says the biggest factor is probably that some colleges are “not properly accounting for the multiple counting of students taking more than one online course” in the figures they provide to the Babson survey. Since the Education Department started requiring colleges to report distance-education enrollments, he says, those institutions have probably become more exacting in their tracking of those numbers.

The reporting requirements for the department “are such that I would always trust their numbers over ours,” he wrote. “However, I still believe that the trends we have reported for the past 11 years are very much real.”

The Education Department probably will not release its 2013 numbers on total distance-education enrollments for some time. But if last year’s report is any indication, it may be well below the Babson group’s 7.1-million estimate.

Now that the Education Department will be collecting accurate enrollment data, Mr. Seaman says, the Babson group will probably shift its focus in future versions of the survey to questions about the attitudes and objectives around online education.