I'm currently beginning research that involves an aspect of Professional Development (PD) for Mathematics teachers, but I don't have much experience or knowledge of PD. What are some of the seminal works on PD for Mathematics teachers that I can include in my Literature Review?
In terms of researchers who I am personally familiar with: I would recommend work by Orit Zaslavsky.
From her NYU-Steinhardt bio:
A search in google scholar here has as its top two citations:
For mathematics teachers in general (as opposed to mathematics teacher-educators) see if you can track down the 1994 NCTM yearbook, which had as its focus (and title) "Professional Development for Teachers of Mathematics." It's already 20 years old, but should provide a good starting point.
(Incidentally, checking google scholar for articles on PD that cite the '94 yearbook yields the latter of Zaslavsky's articles cited above as the first result.)
If you are still doing research on PD, here are references specifically related to implementation of reform recommendations. These articles are based on the fact that successful implementation of reform requires most teachers to make fundamental and perhaps even radical changes in their teaching practices.
The latter two references describe the results of an 18-month study on teachers who claimed on a survey to be implementing the 1989 NCTM reform recommendations at a high level in their classrooms. The study found that only four of 25 teachers had actually changed the core of their practice to conform with the reform recommendations. The second article describes the elements of PD of the teachers who were successful in implementing the reforms and those who were not successful. The third article describes the three patterns of practice of the teachers, from most to least consistent with the reform recommendations, and discusses the implications for policy.