You will not be surprised to learn that when Michelle Rhee went to England recently, she spoke of her great success in improving the D.C. public schools.

Her secret? Finding the best teachers and firing the worst teachers.

The only problem with her narrative is that it is not true.

Her IMPACT system was imposed in 2009. Since then, the D.C. public schools have made little progress on state or national exams.

The D.C. public schools continue to have the largest black-white achievement gap of any district assessed by the federal NAEP.

It is not clear whether her method identified the best teachers or the worst teachers, but it is clear that she created a level of turnover among teachers and principals that is staggering.

A recent opinion piece in the Washington Post said:

DCPS has one of the highest teacher turnover rates in the nation. Richard Ingersoll of the University of Pennsylvania estimates that, “nationally, on average, about 20 percent of new public school teachers leave their district to teach in another district or leave teaching altogether within one year, one-third do so within two years, and 55 percent do so within five years.” In DCPS, by contrast, 55 percent of new teachers leave in their first two years, according to an analysis by DCPS budget watchdog Mary Levy. Eighty percent are gone by the end of their sixth year. That means that most of the teachers brought in during the past five years are no longer there. By comparison, in Montgomery County just 11.5 percent leave by the end of their second year, and 30 percent by the end of year five. DCPS has become a teacher turnover factory. It has a hard time keeping teachers who are committed to their school and the community it serves.

Most of the principals that Rhee personally hired have left their schools.

If the British follow her suggestions, they too can have churn without improvement.