The Private School Universe Survey, 2015-16 (PSS 2015-16), is a study that is part of the Private School Universe program. PSS 2015-16 (https://nces.ed.gov/surveys/pss/) is a cross-sectional survey that collects data on private elementary and secondary schools, including religious orientation, level of school, length of school year, length of school day, total enrollment (K-12), race/ethnicity of students, number of high school graduates, number of teachers employed, program emphasis, and existence and type of kindergarten program. The study will be conducted using mail questionnaires, an internet response option and telephone and personal follow-up of all private schools in the United States. The PSS universe consists of a diverse population of schools. It includes both schools with a religious orientation (e.g., Catholic, Lutheran, or Jewish) and nonsectarian schools with programs ranging from regular to special emphasis and special education. Key statistics produced from PSS 2015-16 are on the number of private schools, students, and teachers, the number of high school graduates, the length of the school year and school day.