When education leaders talk about turning around persistently low-performing schools, sooner or later the talk turns to what to do about low-performing teachers.?Proposals for how to address this problem may include closing schools, dismissing or reassigning teachers, and reopening the schools with a new, handpicked faculty.?This is a relatively straightforward "solution," but it is not always feasible.?Some school districts have large numbers of ineffective or mediocre teachers; others are in sparsely populated areas without a ready supply of new hires.?

Aware of these obstacles, some education officials propose "professional development" as an alternative to replacing teachers.?The implication is that professional development is potentially so powerful that it can transform an ineffective teacher into one who can increase student achievement.?It's a seductive vision, but difficult to achieve.?

It isn't clear that education leaders who advocate professional development as a "fix" for low-performing teachers have carefully considered their proposal.?There are many reasons why some teachers are not effective.?The continuum of inadequate performance includes a wide range of pedagogical deficiencies and behavioral anomalies. It requires time and effort to understand why a teacher is not effective, whether professional development is a potential remedy, and how to organize a set of learning experiences that may significantly improve the teacher's performance.?Such a process should be serious and thoughtful; every teacher deserves that. ?

Yet, invoking "professional development" as an antidote to ineffective teaching may be little more than a throwaway line.?It sounds like a reasonable approach, but implementing it is fraught with complications.?Is a school system really committed, or able, to invest the money, time, and talent required to analyze the reasons for a teacher's lack of effectiveness??Does it have the expertise to craft professional development that is responsive to individual teachers' needs??Will a school system support a teacher's engagement in a process of continuous, iterative new learning over time??How will it assess the impact of professional development on a teacher, and what criteria will it use to determine whether the teacher is subsequently effective??

There is no question that effective professional learning can help many teachers broaden and deepen their knowledge and skills.?But professional development is not a broad-brush remedy school systems can easily or appropriately apply to all low-performing teachers.?For professional development to have maximum impact, education leaders must understand what it can and cannot accomplish for specific teachers, with specific needs, working in specific contexts.

Hayes Mizell is NSDC's distinguished senior fellow.