One study is quantifying the increased productivity of on-line classes for professors. The analysis didn’t consider the reduced space needs or savings from students not having to commute to class. Both of those factors would contribute to the productivity improvement.
Conclusion was a reduction in time of between 36% and 57%.
Marginal Revolution blog discusses this in Online Education Trumps the Cost Disease.
Intuitively it makes sense that on-line classes should improve professors productivity, reduce costs for colleges, and reduce dollar & time cost for students. Multiple studies will be necessary before those results can be generally accepted.
Study also concluded that in hybrid classes, students learned the materials in 25% less time.
The study concluded the students learned just as much through the on-line courses as in-class.
Obviously that’s just one study, but I think it is just the start.