A recent study indicates that  online learning is as effective as, if not more, than traditional face to face instruction. According to a meta-analysis conducted by Barbara Means, Yukie Toyama, Robert Murphy, Marianne Bakia and Karla Jones from the Center for Technology in Learning which analyzed 99 studies by comparing on-line and off-line education between the years of 1996 through 2008, online education simply works just fine.  The results have indicated that in general students perform better when instruction is carried out online. What is more surprising is on-line only condition was sometimes better than blended education method (mixed: combination of online and off-line instruction).This finding becomes more obvious if the learners are adults (college students etc.). The authors have two warnings though: 1-We cannot generalize the findings to K-12 students because of the limited sample size, 2- It is actually quite difficult to do a head to head comparison because online education has different pedagogy, time usage and curriculum structure.
Here are the major findings of the study (pages 15-16)

• “Students who took all or part of their class online performed better, on average, than those taking the same course through traditional face-to-face instruction.
• Instruction combining online and face-to-face elements had a larger advantage relative to purely face-to-face instruction than did purely online instruction.
• 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.
• Most of the variations in the way in which different studies implemented online learning did not affect student learning outcomes significantly.
• The effectiveness of online learning approaches appears quite broad across different content and learner types.
• Effect sizes were larger for studies in which the online and face-to-face conditions varied in terms of curriculum materials and aspects of instructional approach in addition to the medium of instruction.
• Blended and purely online learning conditions implemented within a single study generally result in similar student learning outcomes.
• Elements such as video or online quizzes do not appear to influence the amount that students learn in online classes.
• Online learning can be enhanced by giving learners control of their interactions with media and prompting learner reflection.
• Providing guidance for learning for groups of students appears less successful than does using such mechanisms with individual learners.”

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