Much has been written about the sorry state of many inner-city public schools. Numerous factors are cited: incompetent teachers, poverty and social deprivation, petty bureaucratic politics and flabby curricula.

But a constant churning of teachers and students may be an overlooked factor. Mobility has become a major source of concern for school systems across the country as housing costs rise, families change neighborhoods, immigrants stream into America's cities and teachers leave the profession or change schools.

Evictions, job changes, assignment to homeless shelters, even incarceration of a parent -- keeps children in low-income families on the move.

• Experts say that at many poor schools, neither students nor teachers nor principals stay long enough for any curriculum -- innovative or traditional -- to take root.

• Education experts say that one move probably does not hinder learning -- but multiple moves lead to gaps in a child's education.

• The most recent data on student mobility appeared in a 1994 General Accounting Office report which said 17 percent of the country's third-graders -- more than 500,000 children -- attended at least three different schools since starting first grade.

While such churning has existed for years, it has become a significant new focal point for education reform groups.

Source: Lynette Holloway, "As Poverty Shifts Students, Getting Lessons to Stick Proves a Tough Task," New York Times, May 25, 2000.

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