The Northwest Nazarene University (NNU) and the Idaho Digital Learning Academy (IDLA) along with iNACOL have published a research report on blended teaching. You can check out the report here.
A radio show regarding the study is featured here:
http://www.blogtalkradio.com/edutalk/2013/09/17/k-12-online-ed-inacol-on-teacher-transition
And next week, the NNU and IDLA team will be doing a Research in Review Webinar on Tuesday, November 19th, from 3-4pm eastern. Registration is free. Sign up here:
https://www.inacol.org/events/