"Deeper Learning" & "Instructional Leadership" = 3 results

Was shocked to run the combo search terms "deeper learning" and "instructional leadership" in the ERIC (EBSCO) database and return a grand total of 3 results. 

How can this be? I know the concept of "deeper learning" is fairly new at least based on the Hewlett definition, but of all the effort that has gone into the deeper learning movement how can we (mostly) not have formally talked about or investigated instructional leadership? Changing the teaching and learning experience for the child is the core outcome needed by deeper learning and I am not sure how that is possible without serious instructional leadership.