Absolutely, Chris, it can’t be one or the other it has to be both!
I think finding knowledge underpinning librarianship, in general, is easier to find than for school librarians.
We have our professional body called CILIP where best practice and knowledge are shared. There is a lot of research about university libraries which is not surprising as that is where all the researchers are but it is so much more difficult to find research about professional knowledge and school libraries. I think this is because the profession has been severely hit over the last decade and we now have a real cross-section of staff in our school libraries from professionally qualified to professional with CILIP qualifications to those who have no library qualifications at all. They are all doing their best but it is not the same as having a profession like teaching. As much as I love my profession this is just the way that it is at the moment. Hopefully, FOSIL will help bring some change to this. I have not come across any papers regarding professional learning for school librarians but saying that I have not looked recently.
There is a lot of talk on Twitter (one of my favourite places for learning) at the moment about professional learning for school librarians so hopefully, there will be more out there soon. I wrote a blog post (I do a lot of that too…) about CPD for school librarians and I had some interesting comments via Facebook. Many share best practice with public library staff but many work on their own in a school and it can be very isolating.
Hopefully, we will get some on here to share what they understand about professional learning.