LPH has an interesting site that offers empirical research studies about teacher retention, attrition, and mobility.
"... in an average school year, approximately 1,000 teachers quit each school day and on an average school day an additional 1,000 teachers migrate from one school to another. On average, a third of the newly hired teachers leave during their first three years; almost half leave during the first five years (National Commission on Teaching and America's Future [NCTAF], 2003)."...
