US Montessori Private Schools, 1989-2024: A Harmonized Dataset Built From 18 Waves of the NCES Private School Universe Survey

The National Center for Education Statistics (NCES) has surveyed every private school in the United States every two years since 1989-90 through the Private School Universe Survey (PSS). Each wave records whether a school describes itself as Montessori and whether it belongs to a Montessori association, but variable names, codes and coverage change from wave to wave, which makes the Montessori sector hard to follow over time. This deposit contains a data descriptor and the dataset it describes. The dataset extracts every Montessori private school from the 18 public-use PSS files from 1989-90 to 2023-24 into 37,543 school-year records with one consistent set of 32 columns, and adds summary tables by year, state, city, county and locale and a GeoJSON file of the 2,070 schools of 2023-24. The weighted estimate rebuilt from the files reproduces the published NCES figure of 2,441 Montessori schools for 2021-22, and the weighted total of all private schools matches NCES Digest Table 214.10 for every wave from 1997-98 to 2015-16. Files carter-2026-us-montessori-private-schools-data-descriptor.pdf, the data descriptor (sources, harmonization, validation, limits) us-montessori-private-schools-v1.0.zip, the full dataset (CSV, GeoJSON, data dictionary of 115 columns, build scripts, starter notebook, charts) Read with care. Private schools only (public district and charter Montessori schools are not in the PSS). The PSS covers schools that offer kindergarten or a higher grade. "Montessori" and association membership are self-reported and do not indicate accreditation. Compare trends from 1995-96 on. Source data. U.S. Department of Education, National Center for Education Statistics, Private School Universe Survey (PSS), public-use data files, 1989-90 to 2023-24, https://nces.ed.gov/surveys/pss/. US government work, public domain. The same data is maintained on GitHub, Kaggle and Hugging Face. Prepared by Montessori Theory, a site about Montessori at home.