Why are online courses more effective?

A recent story in Inside Higher Ed says:

Online learning has definite advantages over face-to-face instruction when it comes to teaching and learning, according to a new meta-analysis released Friday by the U.S. Department of Education.

A few other quotes:

The study found that students who took all or part of their instruction online performed better, on average, than those taking the same course through face-to-face instruction. Further, those who took "blended" courses -- those that combine elements of online learning and face-to-face instruction -- appeared to do best of all.

The...report...identified more than 1,000 empirical studies of online learning that were published from 1996 through July 2008. For its conclusions, however, the Education Department considered only a small number (51) of independent studies that met strict criteria. They had to contrast an online teaching experience to a face-to-face situation, measure student learning outcomes, use a "rigorous research design," and provide adequate information to calculate the differences.

So why do online courses do a better job of promoting learning?

[M]anipulations that trigger learner activity or learner reflection and self-monitoring of understanding are effective when students pursue online learning.... Notably, the report attributes much of the success in learning online (blended or entirely) not to technology but to time. "Studies in which learners in the online condition spent more time on task than students in the face-to-face condition found a greater benefit for online learning.... [O]nline learning is much more conducive to the expansion of learning time than is face-to-face instruction."

"Online education provides additional opportunities...." "It gives people greater opportunity for flexibility, for experiential learning, for illustrating things in multiple ways such as visualization."

And now, for the rest of the story...