This is such a great question! In Lewisville ISD we collect a lot of data about blended: attendance, completion, grade distribution, demographic, and assessment. But your question is what we are going after now. When I walk our blended classes at the secondary level (students attend class two days a week and learn online three days a week -- at the class vs. program level), I see all of the pieces in your question playing out differently. And how they play out shows up the the rather traditional data we do collect. All to say, we are just now discussing how to conduct research about how students and teachers are spending their time. I'll get back to this question as our discussion deepens.