As the number of charter schools continues to grow, one facet of their autonomy--the ability to set and enforce independent disciplinary standards--has raised difficult questions about whether those schools are pushing out students who pose behavior or academic challenges and how their policies affect regular public schools. Research on the issue…

Some of the students at Success Academy are doing International Baccalaureate-level work. Most of the classes have just five or six students. But this Baltimore public high school isn't for elite students. Admission depends on whether students have done something so serious a regular district school won't have them anymore: assaulting classmates…