In Liberating Learning, Moe and Chubb (2009) suggest that "effective teachers are not easily identified from their credentials, education, or experience (beyond the first few years of teaching)" (95).
Many educators now possess (multiple) Master's or PhDs. To what extent did you degree improve your instruction? How do you know? Are teachers the victims of education inflation?
Graduate school, for me, was about talking to colleagues and sharing tips, tricks, best practices, etc.
I have 3 Masters, all in education (general ed, instructional tech, ed admin) and the classes themselves didn't offer me a whole lot. Gave me some background in theory and history (which I feel are important) but they gave me the opportunity to discuss real world situations, in almost real time, with colleagues.
I did all my education course work at the graduate level, while teaching. I came to the profession from the high-tech/media sector and I found great value in teaching all day and then going to class and being able to share my experiences and have colleagues in much the same situation help me to reflect, evaluate, plan, etc.
I tend to be a bit of a contradiction. I think college and graduate school are amazing things that need to be experienced but I think the classes, in general, are pretty worthless. What I find valuable are the connections, experiences, and different lense they offer and provide that I couldn't get by working alone.
A 3rd grade teacher I work with has this quote on her wall:
Perhaps the most valuable result of all education is the ability to make yourself do the thing you have to do, when it ought to be done, whether you like it or not.
My Master's was in Curriculum and Instruction with Technology. In some ways, it helped improve my teaching, because I started to think of new ways of doing things. However, just like most education classes, it wasn't that helpful. On the positive side of things, I felt that the graduate classes were more focused on the way things are, whereas my undergraduate education program was more focused on how the professors thought things were. (I actually had a professor tell us that to make a high school senior stop talking in class, all we had to do was place a hand on their shoulder, and they'd stop. We cheerfully informed her that the senior would most likely grasp our hand and say something like "How you doing, sweetheart?")
I have found that I learned far more about teaching just by teaching, than I ever did from taking classes.
I think that the usefulness is dependent upon the program. For my M.S. program (Ed Tech) my professors were ardent practitioners of authentic learning. They made it very clear that whatever we chose to do (for our various tech projects/assignments) should be connected to what we're doing in the classroom with our students otherwise it would not be meaningful for anyone. Now, that posed a problem for the new teachers in the program who were substitutes or who did not have a classroom at all, but for me, it was an invaluable experience. I got a lot more out of that program than I thought I would. Everything that I did or created in that class was integrated in some form into my curriculum. My students were learning right along with me. I don't know how many programs out there are as relevant and flexible as the one I was in, but if you're looking for a master's program in Ed Tech and if you're not afraid of hard work, check out California State University, Fullerton's M.S. Program in Ed Tech. It's a fully online program with a couple of really great professors. =)