Online course enrollment is booming.

In the fall of 2011, more than 6.7 million students (or about a third of college students) were enrolled in at least one online course, according to a 2012 study conducted by the Babson Survey Research Group. It's clear online courses now play a major part in higher education, and online enrollment numbers continue to grow at a rapid rate. For instance, online course enrollment grew by 570,000 students from fall 2010 to 2011, and when you look at the facts about online courses, many trends begin to appear.

Online Education at Traditional Colleges

Traditional universities are integrating online education, and the number of online course offerings will continue to grow. The 2012 Babson survey found that almost 70 percent of higher education officials said online courses were "critical to their long-term strategy."

Are They Better Than Face-to-Face Cources?

Most of the data suggest that online courses are as good as or slightly better than their traditional counterparts. A 2009 study from the Department of Education found that students in online courses scored slightly higher on exams, and on average, they fared better than traditional students. The point is also something administrators agree on. According to the Babson survey, 77 percent of academic leaders say online courses are the same as or superior to face-to-face learning.

Lower Retention Rates

One problem with online courses is that they have lower completion rates. A 2011 Columbia University study found that the completion rates for online courses at community colleges in Washington were about 8 percent lower than traditional classes. In fall 2009, at the University of Phoenix -- the country's largest online higher education institute -- the retention rate for first-time, full-time students is just 38 percent. However, some strictly online universities are more successful at keeping students on track: for instance, American Public University, the number two online degree-granting institution, had a retention rate of 92 percent of first-time, full-time students in fall 2009.

Enrollment Is Booming

From 2003 to 2011, online enrollment jumped from 11.7 percent of total higher education enrollment to 32 percent. That's a huge jump, and it's likely the trend will continue at a modest rate. Although 2011 was the 10th year in a row that online enrollment grew, it's likely the gain of roughly 9 percent in enrollment is hitting a plateau. For instance, in fall of 2005 the year-over-year gain in online enrollment was almost 40 percent.