Do qualifying rules change how people race?
Only 1 city met both-period sample requirements near the faster standard. Among those close finishes, 51.3% were at or below it in 2016–2017 and 58.8% in 2019. This narrow comparison cannot establish that the qualifying-rule change altered pacing.
This initial analysis focuses on ages 18–31 in 2016–2017 and 2019; it does not assign individual Boston eligibility or acceptance.
How we measured it. The B.A.A. history lists 18–34 standards of 3:05 for men and 3:35 for women for 2013–2019 Boston races; the 2020 standards became 3:00 and 3:30, announced in September 2018. Compare 2016–2017 performances with 2019, excluding the transition year. Exact ages 18–31 avoid crossing the 35-year boundary within the next two years.
Full methodology & sources
Around each fixed old/new benchmark, select finishes within ±2 minutes. Within each city and period, calculate the share at or below the benchmark. Keep cities with at least 20 close finishes in both periods and weight both periods by the smaller city-period count. Report at least 100 observed finishes per displayed period.
Acceptance cutoffs, declared intentions, age on a future Boston race day, certification and qualifying windows are not assigned to individuals. Round-number appeal, historical field changes and anticipatory behavior can explain bunching. This is not a difference-in-differences causal estimate, and the comparison does not cover every rule change.
Official sources: https://www.baa.org/races/boston-marathon/qualify/ ; https://www.baa.org/news/2020-boston-marathon-qualifier-acceptances-announced/ . Historical values verified 2026-09-08.
Use complete, strictly increasing elapsed checkpoints at 3.11, 6.21, 9.32, 12.43, 15.53, 18.64, 21.75, 24.85 and 26.22 mi. Clock strings must parse as H:MM:SS or M:SS. No missing splits are interpolated.
Remove exact duplicate race records, ignoring database IDs, ingestion timestamps and source URLs. Retain finishes from 90 minutes to 12 hours with every section between 3.22 and 32.19 minutes/mi. These quality filters can exclude genuine unusual performances; the analysis describes this eligible cohort, not every entrant.
Full source records are available in public GitHub Releases. These chart tables require at least 100 eligible observations per cell for estimate reliability. Counts refer to finishes, linked pairs or event observations as specified in that answer.
These are observational results. Fitness changes, intentions, training, selection into the dataset and unmeasured conditions can explain differences. Outcome percentiles describe variation among performances, not confidence intervals or advice about the best strategy.
Apply the reviewed source-quality edition exclusions for this exact export after the timing checks. Known invalid split grids, incomplete ingestion, unreconciled HOLD editions and a selected top-finisher field do not contribute to the analyses or prior benchmarks. Report source exclusions separately; an already invalid timing row is not counted twice. Missing age or recorded gender alone does not exclude an otherwise eligible finish from the overall cohort. Other sparse editions are not declared incomplete merely from their size.
At or below the benchmark among nearby finishes
Percent (%)
View exact values and sample sizes
| Group | At or below the benchmark among nearby finishes | Observations |
|---|---|---|
| 2016–2017 races | 51.3% | 279 |
| 2019 races | 58.8% | 153 |