Recent research by the National Center for Education Statistics found that eight percent of public school teachers—and fully 20 percent of those with no prior full-time teaching experience—left the classroom in the 2004-05 school year. The NCES's researchers suggest that lack of professional autonomy may be partly to blame. Others point, relatedly, to growing pressures on teachers as a result of standards and accountability initiatives, and a feeling that the profession is not personally rewarding.
Teacher Magazine had the good sense to ask teachers and others to comment on the research and share their own stories about departures from the profession. There's some predictable whining but you'll also find very thoughtful reflections, including a list of Why's from education consultant Jim Downey, "most of which involve political gamesmanship between parties that have little to do with what happens in the classroom, or the school in general, but have a great impact on how teachers are allowed to do the job."