There are three types of preparatory schools in the US

• Boarding Schools - where students reside
• Day Schools – no residential facilities for students
• Boarding/Day Schools - provide some residential services to out-of-area students and also admit students to the day-school programs.
• Some schools admit students of only one sex; others are co-educational
• Prep schools are selective, academically challenging, and largely independent of state and local control

• Very low student-to-teacher ratio allows special attention to each student
• The tuition allows schools to hire highly-qualified teachers and retain them in tenure
• These schools often have significant endowments and often finance scholarships to promote demographic diversity