L. Terbeek, M. Cremer, C.B.P.J. van Klaveren

Blended learning, in which online and face-to-face learning activities are combined, is central to educational innovation within a rapidly growing number of educational institutions worldwide. The popularity of blended learning is somewhat remarkable, because it is premised on the belief it yields better educational outcomes, not on rigorous scientific evidence. In this study we discuss the findings of our review of empirical literature on blended learning and its implications of the described interventions on the measured outcomes; efficiency, effectiveness, motivation and costs. We determine what we know about blended learning and based on this what we need to know about it by systematically determining similarities and differences from three perspectives. Firstly, we determine the effects of the, so characteristic for blended learning use of learning technology, on measured outcomes of the interventions. Secondly, by distinguishing three intervention components; teaching method, learning activity and learning technology, we determine intervention types. This classification allows us to identify comparable studies. Thirdly, we use the Community of Inquiry (CoI) framework, our extensive version of the associated code template of the CoI framework and the validated CoI survey to review the comparable studies in more detail. This study has added value in several regards, it is the first one to conceptualize and compare blended learning interventions by using our expanded version of the original Community of Inquiry (CoI) framework code template, where we add a careful distinction between online and face-to-face activities related to the categories of the teaching and social presence. As a result we offer an overview that contributes substantially to the understanding of the dynamic and complex phenomenon blended learning. Based on our review findings we identify gaps in existing blended learning research, which allows us to provide recommendations and guidelines for future systematic blended learning research, that appears to be very urgent. Beyond its scientific contribution, this review is informative for educational technologists, teachers, policy makers, and directors of education.