A shift to greater school-level control of teacher professional development may be responsible for "perceptual discrepancies" over who is primarily responsible for organizing teachers’ learning activities, according to a survey of 1400 teachers, principals, and district superintendents. Principals and teachers in larger schools tended to have the greatest sense of school-level influence over professional development; however, in low-income schools, district administrators were perceived to have more authority. Districts were seen as the main source of financial support for teacher professional development, but the findings "also suggest a fair amount of discretionary authority at the school level to select and purchase materials and services specific to their needs."
PBS Teacher Line/Hezel Associates.(2007). The PBS TeacherLine National Survey of Teacher Professional Development. Syracuse, NY: Hezel Associates.
A good research roundup on this topic is available at: http://www.teachermagazine.org/tm/articles/2007/10/25/01report-1.h01.html?tmp=612090635