Change by state, 2018-19 to 2025-26

What this dataset measures

Built to test whether girls' high school sports participation fell in states after they passed laws like Washington Initiative IL26-638. NFHS is the only national source of participation by state and sex; Census estimates give per-capita denominators.

Geography

United States, 50 states and the District of Columbia

Unit of observation

State (or DC) by school year

Update cadence

Annual, after each NFHS survey (usually August)

Curator

FactHub Research Team

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

• parse.js Transformation manifest · text/javascript · 1.3 KB (1,350 bytes)

  Reads the Totals by State table from each NFHS survey (pdftotext -raw output).

• sport.js Transformation manifest · text/javascript · 1.8 KB (1,829 bytes)

  Reads one girls' sport column by state from the NFHS survey (pdftotext -table output); used for wrestling and 2025-26 flag football.

• analyze.js Transformation manifest · text/javascript · 4.4 KB (4,464 bytes)

  Joins NFHS totals, law groups and Census population into the state-year panel and computes group series.

• analyze2.js Transformation manifest · text/javascript · 6.6 KB (6,735 bytes)

  Computes every difference-in-differences estimate, robustness check and table in this dataset.

• build-csv.js Transformation manifest · text/javascript · 1.1 KB (1,139 bytes)

  Writes the two CSV tables from the computed panel.

• laws.json Transformation manifest · application/json · 2.9 KB (2,984 bytes)

  Law list used by the scripts (same content as state-laws.csv).

• f2425.json Transformation manifest · application/json · 328 bytes

  Girls' flag football by state, 2024-25, transcribed from the NFHS other-sports list; sums to the national 68,847.

• f1819.json Transformation manifest · application/json · 112 bytes

  Girls' flag football by state, 2018-19, transcribed from the NFHS other-sports list; sums to the national 11,209.

• README.md Documentation · text/markdown · 1.8 KB (1,823 bytes)

  How to reproduce the tables and analyses from the NFHS and Census files.

• dataset-parts.json Documentation · application/json · 62.1 KB (63,603 bytes)

  Machine-readable copy of version 1 sources, tables, events and saved analyses (version 2 adds four analyses and two sources, listed in the changelog).

• v2-checks.js Transformation manifest · text/javascript · 4.9 KB (5,027 bytes)

  Computes the catch-up regression, the timing table and the universal-verification comparison added in version 2.

Saved analyses

Sources

1. NFHS High School Athletics Participation Survey, 2015-16 Participation counts by state and sex (Totals by State table) for 2015-16

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

2. NFHS High School Athletics Participation Survey, 2016-17 Participation counts by state and sex (Totals by State table) for 2016-17

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

3. NFHS High School Athletics Participation Survey, 2017-18 Participation counts by state and sex (Totals by State table) for 2017-18

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

4. NFHS High School Athletics Participation Survey, 2018-19 Participation counts by state and sex (Totals by State table) for 2018-19, plus girls' wrestling and flag football by state

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

5. NFHS High School Athletics Participation Survey, 2021-22 Participation counts by state and sex (Totals by State table) for 2021-22

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

6. NFHS High School Athletics Participation Survey, 2022-23 Participation counts by state and sex (Totals by State table) for 2022-23

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

7. NFHS High School Athletics Participation Survey, 2023-24 Participation counts by state and sex (Totals by State table) for 2023-24

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

8. NFHS High School Athletics Participation Survey, 2024-25 Participation counts by state and sex (Totals by State table) for 2024-25, plus girls' wrestling and flag football by state

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

9. NFHS High School Athletics Participation Survey, 2025-26 Participation counts by state and sex (Totals by State table) for 2025-26, plus girls' wrestling and flag football by state

   Retrieved October 23, 2026. NFHS copyright; factual figures used with attribution. Derived state totals republished with attribution; the PDF itself is linked, not hosted.

   Reliability: Other. The National Federation of State High School Associations compiles counts reported by its 51 member state associations. A student in two sports counts twice. The survey takes no position on state eligibility laws.

10. NFHS news release (August 2026): Led by Girls Flag Football and Girls Wrestling, High School Sports Participation Increases for Fifth Consecutive Year National 2025-26 totals and the growth of girls' flag football and wrestling

    Retrieved October 23, 2026. NFHS copyright; quoted with attribution. Linked, not hosted.

    Reliability: Other. Has a stake in this finding. NFHS promotes high school sports and reports on its own survey; its framing of growth is promotional, but the figures match the survey tables.

11. U.S. Census Bureau, Annual Estimates of the Civilian Population by Single Year of Age and Sex for States, 2010-2019 (SC-EST2019-AGESEX-CIV) July 1, 2015-2018 civilian population ages 14-17 by sex and state (denominators for 2015-16 to 2018-19) Free copy

    Retrieved October 23, 2026. Public domain (U.S. government work). Aggregates republished.

    Reliability: Government. Census Bureau population estimates (Vintage 2019), built from the 2010 Census plus births, deaths and migration.

12. U.S. Census Bureau, Annual Estimates of the Civilian Population by Single Year of Age and Sex for the United States and States: April 1, 2020 to July 1, 2025 (SC-EST2025-AGESEX-CIV) July 1, 2021-2025 civilian population ages 14-17 by sex and state (denominators for 2021-22 to 2025-26) Free copy

    Retrieved October 23, 2026. Public domain (U.S. government work). Aggregates republished.

    Reliability: Government. Census Bureau population estimates (Vintage 2025), built on the 2020 Census base; not strictly continuous with Vintage 2019.

13. Idaho Legislature, House Bill 500 (2020), Fairness in Women's Sports Act: bill status Idaho enactment date (signed March 30, 2020; effective July 1, 2020)

    Retrieved October 23, 2026. Public government record. Linked.

    Reliability: Government. Official legislative status page; the page notes status updates are unofficial until the journal.

14. NPR, Tennessee Becomes 3rd State This Month To Enact Restrictions For Transgender Athletes (March 27, 2021) Enactment dates for the Mississippi, Arkansas and Tennessee laws

    Retrieved October 23, 2026. News report; cited. Linked.

    Reliability: News report. National news report written at the time of signing.

15. ESPN, Transgender athlete laws by state: Legislation, science, more (August 2023) State-by-state bill numbers and enactment dates for laws enacted 2020-2023, and court blocks

    Retrieved October 23, 2026. News report; cited. Linked.

    Reliability: News report. State-by-state tracker compiled by ESPN reporters; dated August 2023, so it predates the 2024-2025 laws.

16. Trans Athlete (transathlete.com), state policy tracker, Take Action page Wyoming enactment date; Alaska and Virginia listed as policy, not law; count of 29 states

    Retrieved October 23, 2026. Advocacy page; cited. Linked.

    Reliability: Advocacy group. Maintained by an advocate for transgender athletes' inclusion, which opposes these laws; used only for dates and classifications.

17. Axios Columbus, Ohio bill restricting trans health care to take effect in 90 days (January 24, 2024) Ohio HB 68 veto override date

    Retrieved October 23, 2026. News report; cited. Linked.

    Reliability: News report. Local news report on the Senate override vote.

18. New Hampshire Bulletin, Sununu signs bans on trans girls in girls' sports, gender affirming surgeries for minors (July 19, 2024) New Hampshire HB 1205 signing date

    Retrieved October 23, 2026. News report; cited. Linked.

    Reliability: News report. Nonprofit state news outlet reporting the signing.

19. Office of Governor Jim Pillen, Governor Pillen Signs the Stand With Women Act (June 4, 2025) Nebraska LB 89 signing date

    Retrieved October 23, 2026. Public government record. Linked.

    Reliability: Government. Has a stake in this finding. Press release from the governor who signed the law.

20. Nebraska Legislature, LB 89 (2025), Stand With Women Act, slip law Nebraska requirement that every athlete give a doctor-signed document confirming sex

    Retrieved October 23, 2026. Public government record. Linked.

    Reliability: Government. Official slip law published by the Nebraska Legislature.

21. Oklahoma Legislature, SB 2 (2022), enrolled Oklahoma requirement of an annual parent affidavit of sex for every athlete

    Retrieved October 23, 2026. Public government record. Linked.

    Reliability: Government. Enrolled bill text published by the Oklahoma Legislature.

Limitations and reproducibility

Reproducible: All inputs are public. The scripts (artifacts) parse the NFHS PDFs, join Census estimates, and compute every analysis; the README lists the steps. Extracted columns were checked against NFHS national totals.

• Observational: the law states differ from the others (mostly Southern, Plains and Mountain West states with Republican legislatures). A difference in trends is not proof that the laws caused it.
• NFHS figures are reported by each state association and are not audited. Some states repeat an earlier year exactly (Ohio 2022-23 and 2023-24; Connecticut, Delaware, Louisiana, Maine, Vermont and DC in some years), and some jump by more than 25% in a year (for example Vermont +103%, Kentucky +38% and Washington +28% in 2025-26).
• Counts are participation entries, not unique students: a student in two sports counts twice.
• No survey for 2019-20 or 2020-21 (COVID-19). Pandemic limits on school sports lasted longer in some no-law states, which may have slowed their recovery.
• Girls' flag football and wrestling grew fast after 2021, and flag football was sanctioned first in several Southern law states; a version excluding both sports is included.
• The laws differ (grades covered, how sex is established, enforcement), and some were blocked in court for some or all students (Idaho, Utah, Arizona; West Virginia and New Hampshire for named plaintiffs).
• None of these laws requires every girl to have her sex verified by a health care provider as I-638 Sec. 3(2) would; this data cannot test that requirement.
• Census Vintage 2019 (for 2015-2018) and Vintage 2025 (for 2021-2025) use different census bases.
• A federal executive order of February 2025 applied nationwide, so in 2024-25 and 2025-26 the comparison is between states with and without their own law.
• Law states started with lower girls' participation (370 vs 453 per 1,000 in 2018-19), and after the pandemic gap lower-rate states gained more; part of the law states' faster gain may be catch-up (see catch-up-check).