{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T05:46:06Z","timestamp":1790833566321,"version":"4.1.0"},"reference-count":65,"publisher":"National Academy of Sciences","issue":"43","license":[{"start":{"date-parts":[[2025,10,20]],"date-time":"2025-10-20T00:00:00Z","timestamp":1760918400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"name":"U.S. Department of Education, Institute for Education Sciences","award":["R305A180181"],"award-info":[{"award-number":["R305A180181"]}]},{"DOI":"10.13039\/100014848","name":"Arnold Ventures","doi-asserted-by":"publisher","award":["23-10339"],"award-info":[{"award-number":["23-10339"]}],"id":[{"id":"10.13039\/100014848","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007039","name":"Brady Education Foundation","doi-asserted-by":"publisher","award":["NA999"],"award-info":[{"award-number":["NA999"]}],"id":[{"id":"10.13039\/100007039","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2025,10,28]]},"abstract":"<jats:p>\n                    Although seminal studies from the early 1960s suggested quality preschool can have lasting positive effects, agreement is lacking on the efficacy of different preschool models. The Montessori model is longstanding but lacks rigorous impact studies; prior random lottery studies included just one or two schools, among other compromises. Here, we report on end-of-kindergarten (age 5 to 6) impacts from a national study of public Montessori preschool. We compared children offered a Montessori seat via competitive lottery admission processes at one of 24 public Montessori schools at age 3 (\n                    <jats:inline-formula>\n                      <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" display=\"inline\" overflow=\"scroll\">\n                        <mml:mrow>\n                          <mml:mi>n<\/mml:mi>\n                          <mml:mo>=<\/mml:mo>\n                          <mml:mn>242<\/mml:mn>\n                        <\/mml:mrow>\n                      <\/mml:math>\n                    <\/jats:inline-formula>\n                    ) to children not offered a seat (\n                    <jats:inline-formula>\n                      <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" display=\"inline\" overflow=\"scroll\">\n                        <mml:mrow>\n                          <mml:mi>n<\/mml:mi>\n                          <mml:mo>=<\/mml:mo>\n                          <mml:mn>346<\/mml:mn>\n                        <\/mml:mrow>\n                      <\/mml:math>\n                    <\/jats:inline-formula>\n                    ), estimating Montessori impacts with intention-to-treat and complier average causal effect models. Roughly half of the treatment sample still attended Montessori for kindergarten. Although there were no notable impacts at the end of PK3 or PK4, at the end of kindergarten, controlling for baseline scores and demographics, Montessori children had significantly higher reading, short-term memory, theory of mind, and executive function scores. Intention-to-treat effect sizes exceeded a fifth of a SD, considered large in field-based school research [M. A. Kraft,\n                    <jats:italic toggle=\"yes\">Educ. Res.<\/jats:italic>\n                    <jats:bold>49<\/jats:bold>\n                    , 241\u2013253 (2020)]. This contrasts sharply with the more typical finding, where impacts of preschool are observed immediately following the program but disappear by the end of kindergarten. Further, a cost analysis suggested three years of public Montessori preschool costs less per child than traditional programs, largely due to Montessori having higher child:teacher ratios in PK3 and PK4. Although sensitivity and robustness analyses yielded similar results, important limitations of the study should be noted.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2506130122","type":"journal-article","created":{"date-parts":[[2025,10,20]],"date-time":"2025-10-20T19:02:56Z","timestamp":1760986976000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":10,"title":["A national randomized controlled trial of the impact of public Montessori preschool at the end of kindergarten"],"prefix":"10.1073","volume":"122","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9697-6611","authenticated-orcid":false,"given":"Angeline S.","family":"Lillard","sequence":"first","affiliation":[{"name":"Department of Psychology","place":["Charlottesville"]},{"name":"University of Virginia","place":["Charlottesville"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-6564-3867","authenticated-orcid":false,"given":"David","family":"Loeb","sequence":"additional","affiliation":[{"name":"Division of Policy, Organizations, Leadership, and Systems, Graduate School of Education","place":["Philadelphia"]},{"name":"University of Pennsylvania","place":["Philadelphia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juliette","family":"Berg","sequence":"additional","affiliation":[{"name":"American Institutes for Research","place":["Chapel Hill"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maya","family":"Escueta","sequence":"additional","affiliation":[{"name":"American Institutes for Research","place":["Chapel Hill"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karen","family":"Manship","sequence":"additional","affiliation":[{"name":"American Institutes for Research","place":["Chapel Hill"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alison","family":"Hauser","sequence":"additional","affiliation":[{"name":"American Institutes for Research","place":["Chapel Hill"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-6229-1820","authenticated-orcid":false,"given":"Emily D.","family":"Daggett","sequence":"additional","affiliation":[{"name":"Department of Psychology","place":["Charlottesville"]},{"name":"University of Virginia","place":["Charlottesville"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2025,10,20]]},"reference":[{"key":"e_1_3_4_1_2","unstructured":"H. Yoshikawa . \u201cInvesting in our future: The evidence base on preschool education\u201d (Tech. Rep. Society for Research in Child Development 2013)."},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1177\/2332858419828690"},{"key":"e_1_3_4_3_2","doi-asserted-by":"crossref","unstructured":"A. Baulos J. L. Garc\u00eda J. J. Heckman Perry Preschool at 50: What lessons should be drawn and which criticisms ignored? https:\/\/doi.org\/10.3386\/w32972 (Accessed 3 October 2025).","DOI":"10.3386\/w32972"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1207\/S1532480XADS0601_05"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.adn2141"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1177\/1529100620915848"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1037\/dev0001115"},{"key":"e_1_3_4_8_2","unstructured":"D. A. Philips . \u201cPuzzling it out: The current state of scientific knowledge on pre-kindergarten effects\u201d (Tech. Rep. Brookings 2017)."},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ecresq.2018.03.005"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1037\/dev0001301"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1177\/2332858418757735"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1080\/03004430.2020.1832998"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.17161\/jomr.v8i2.18675"},{"key":"e_1_3_4_14_2","volume-title":"The Discovery of the Child","author":"Montessori M.","year":"2017","unstructured":"M. Montessori, The Discovery of the Child (Montessori-Pierson Publishing, Amsterdam, The Netherlands, 2017), vol. 2."},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.17161\/jomr.v5i1.7716"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.17161\/jomr.v2i2.5848"},{"key":"e_1_3_4_17_2","first-page":"1","article-title":"The Montessori preschool landscape in the United States: History, programmatic inputs, availability, and effects","volume":"2019","author":"Ackerman D. J.","year":"2019","unstructured":"D. J. Ackerman, The Montessori preschool landscape in the United States: History, programmatic inputs, availability, and effects. ETS Res. Rep. Ser. 2019, 1\u201320 (2019).","journal-title":"ETS Res. Rep. Ser."},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1080\/10888691.2018.1537791"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1080\/10888691.2017.1398649"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.17161\/jomr.v5i1.9788"},{"key":"e_1_3_4_21_2","volume-title":"Montessori: The Science Behind the Genius","author":"Lillard A. S.","year":"2017","unstructured":"A. S. Lillard, Montessori: The Science Behind the Genius (Oxford University Press, Oxford, UK\/New York, NY, ed. 3, 2017).","edition":"3"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1002\/cl2.1330"},{"key":"e_1_3_4_23_2","doi-asserted-by":"crossref","unstructured":"A. S. Lillard N. Else-Quest Evaluating Montessori education. Science 313 1893\u20131894 (2006).","DOI":"10.1126\/science.1132362"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.3389\/fpsyg.2017.01783"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1111\/cdev.13575"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.2307\/1165878"},{"key":"e_1_3_4_27_2","unstructured":"W. W. Clearinghouse \u201cWhat Works Clearinghouse procedures and standards handbook version 5.0\u201d (Tech. Rep. U.S. Department of Education Institute of Education Sciences National Center for Education Evaluation and Regional Assistance (NCEE) 2022)."},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsta.2009.0127"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1111\/cdev.13308"},{"key":"e_1_3_4_30_2","unstructured":"S. Schwartz Reading scores fall to new low on NAEP fueled by declines for struggling students. Education Week (29 January 2025)."},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1037\/0012-1649.33.6.934"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1007\/s11145-013-9439-2"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev-psych-120710-100422"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1037\/0012-1649.40.2.177"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cedpsych.2023.102182"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1207\/S15326942DN1903_3"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1467-8624.2007.01019.x"},{"key":"e_1_3_4_38_2","doi-asserted-by":"publisher","DOI":"10.1037\/dev0001533"},{"key":"e_1_3_4_39_2","doi-asserted-by":"publisher","DOI":"10.1511\/2013.104.1"},{"key":"e_1_3_4_40_2","doi-asserted-by":"publisher","DOI":"10.1037\/bul0000227"},{"key":"e_1_3_4_41_2","doi-asserted-by":"publisher","DOI":"10.1037\/dev0000140"},{"key":"e_1_3_4_42_2","doi-asserted-by":"publisher","DOI":"10.1111\/cdev.12372"},{"key":"e_1_3_4_43_2","unstructured":"A. S. Lillard The Montessori Difference: Evaluating the Evidence (Oxford University Press in press)."},{"key":"e_1_3_4_44_2","unstructured":"A. Skoog-Hoffman . \u201cSocial and emotional learning in U.S. schools: Findings from Casel\u2019s nationwide policy scan and the American Teacher Panel and American School Leader Panel surveys\u201d (Tech. Rep. RAND Corporation 2024)."},{"key":"e_1_3_4_45_2","doi-asserted-by":"publisher","DOI":"10.3102\/0013189X20912798"},{"key":"e_1_3_4_46_2","doi-asserted-by":"publisher","DOI":"10.3102\/0013189X19848729"},{"key":"e_1_3_4_47_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ecresq.2023.11.008"},{"key":"e_1_3_4_48_2","doi-asserted-by":"publisher","DOI":"10.3102\/0162373716689489"},{"key":"e_1_3_4_49_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0170256"},{"key":"e_1_3_4_50_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4073\/csr.2018.10","article-title":"Small class sizes for improving student achievement in primary and secondary schools: A systematic review","volume":"14","author":"Filges T.","year":"2018","unstructured":"T. Filges, C. S. Sonne-Schmidt, B. C. V. Nielsen, Small class sizes for improving student achievement in primary and secondary schools: A systematic review. Campbell Syst. Rev. 14, 1\u2013107 (2018).","journal-title":"Campbell Syst. Rev."},{"key":"e_1_3_4_51_2","volume-title":"The Child, Society and the World: Unpublished Speeches and Writings","author":"Montessori M.","year":"1989","unstructured":"M. Montessori, The Child, Society and the World: Unpublished Speeches and Writings (CLIO, Oxford, UK, 1989)."},{"key":"e_1_3_4_52_2","doi-asserted-by":"publisher","DOI":"10.1016\/0010-0285(88)90014-X"},{"key":"e_1_3_4_53_2","doi-asserted-by":"publisher","DOI":"10.1080\/02568543.2023.2283202"},{"key":"e_1_3_4_54_2","doi-asserted-by":"publisher","DOI":"10.3389\/fdpys.2025.1546451"},{"key":"e_1_3_4_55_2","doi-asserted-by":"publisher","DOI":"10.1080\/10409289.2024.2423275"},{"key":"e_1_3_4_56_2","doi-asserted-by":"crossref","unstructured":"A. K. Murray C. Daoust \u201cFidelity issues in Montessori research\u201d in The Bloomsbury Handbook of Montessori Education A. K. Murray E. T. Ahlquist M. K. McKenna M. Debs Eds. (Bloomsbury Academic London UK 2023) pp. 199\u2013208.","DOI":"10.5040\/9781350275638.ch-20"},{"key":"e_1_3_4_57_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsp.2012.01.001"},{"key":"e_1_3_4_58_2","doi-asserted-by":"publisher","DOI":"10.17161\/jomr.v2i1.5678"},{"key":"e_1_3_4_59_2","doi-asserted-by":"publisher","DOI":"10.1007\/s00362-019-01098-8"},{"key":"e_1_3_4_60_2","volume-title":"Design Sensitivity: Statistical Power for Experimental Research","author":"Lipsey M. W.","year":"1990","unstructured":"M. W. Lipsey, Design Sensitivity: Statistical Power for Experimental Research (Sage Publications Inc., Thousand Oaks, CA, 1990)."},{"key":"e_1_3_4_61_2","doi-asserted-by":"publisher","DOI":"10.3102\/0013189X19891955"},{"key":"e_1_3_4_62_2","volume-title":"Classroom Assessment Scoring System\u2122: Manual K-3.","author":"Pianta R. C.","year":"2008","unstructured":"R. C. Pianta, K. M. La Paro, B. K. Hamre, Classroom Assessment Scoring System\u2122: Manual K-3. (Paul H. Brookes Publishing Co., Baltimore, MD, 2008)."},{"key":"e_1_3_4_63_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ecresq.2024.10.003"},{"key":"e_1_3_4_64_2","doi-asserted-by":"publisher","DOI":"10.4135\/9781483396514"},{"key":"e_1_3_4_65_2","unstructured":"A. S. Lillard Dataset for a national randomized controlled trial of the impact of public Montessori preschool on children\u2019s kindergarten outcomes. Open Science Framework. https:\/\/osf.io\/vuc42\/. Deposited 28 August 2025."}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2506130122","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,20]],"date-time":"2025-10-20T19:03:18Z","timestamp":1760986998000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/10.1073\/pnas.2506130122"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,20]]},"references-count":65,"journal-issue":{"issue":"43","published-print":{"date-parts":[[2025,10,28]]}},"alternative-id":["10.1073\/pnas.2506130122"],"URL":"https:\/\/doi.org\/10.1073\/pnas.2506130122","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,20]]},"assertion":[{"value":"2025-03-18","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-09-20","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-10-20","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e2506130122"}}