Observed finish-time distributions across London, Boston and Chicago — with Tokyo not reported.
Sports Evidence Lab169,902 valid finish times30 event-year groups6 min read
Identity-linked resultsDescriptive, unadjustedGrounded against live dataFull audit trail
169,902
Valid finish times
of 169,904 observed result records
30
Included event-year groups
all passed inclusion for analysis
3
Reported marathon majors
London · Boston · Chicago
The lead insight
Marathons are the same distance, but their finish fields are not the same shape.
In this observed dataset, Boston sits faster, its field concentrated in the quicker bands. Chicago sits closer to the middle. And London shows a broader spread, with more finishers across the longer bands.
The overall field
Where the finishers cluster
Every valid finish time falls into one of five broad bands. Across all 30 included event-year groups, this is the observed shape of the field.
share of 169,902 valid finish times
34.79%
31.96%
17.27%
Under 3:00
8.14%
3:00 to 3:59
34.79%
4:00 to 4:59
31.96%
5:00 to 5:59
17.27%
6:00 plus
7.85%
Two in three observed finishes land between 3:00 and 5:00. The bands are equal in width of clock time, not in share of the field.
The reported majors
Three fields, three shapes
The same five bands, read across each pooled marathon major. The contrast is in the shape of the bar, not just the median beneath it.
A broad mass-participation shape, close to the overall field.
A note on coverage: Tokyo
Tokyo is not reported here because no event-year group passed inclusion. We only report a major once a group meets the quality thresholds for valid, parsed finish times — so where the evidence isn't there yet, we leave the space honestly empty rather than fill it.
Find where you fit
You've seen the shape of the field. The one place it can't show yet is your own.
These distributions are observed across thousands of result records. Bring your own finishes and we'll place you within the pattern — never a prediction, just where you sit in the evidence.
In full view
How we read this, and what it can't say
How the study was built
We built an inventory of marathon event-year groups and applied quality checks, retaining only groups with sufficient valid, parsed finish times. Each valid record was mapped to one of five bands: under 3:00; 3:00–3:59; 4:00–4:59; 5:00–5:59; 6:00 plus. We then aggregated counts, percentages and median finish times by event-year and pooled them by event family. Small cells were withheld under SEL small-cell policy before publishing. Sensitivity checks on inclusion decisions were recorded.
What this study can and cannot say
This study uses observed result records only. A result record is not the same as a person, and the article should not make claims beyond the included event-level finish data.
The figures count result records, not verified individual people. The same finisher appearing in two event-years is counted as two records.
Some small cells are suppressed under SEL policy; 31 cells were withheld in this run.
Finish-time coverage varies by event and year; missing or unparseable times are excluded from every finish-time calculation.
Tokyo is not reported, because no event-year group passed inclusion.
No identity matching or person-level linkage is used anywhere in this analysis: counts are observed result records at event-year level, and the same finisher appearing in two event-years is two records.
Published band cells are small-cell suppressed at the existing SEL policy (cells below 10 withheld); 31 cell(s) were suppressed in this run.
These are descriptive distributions of observed result records at event and event-year level. They do not explain why the shapes differ, attribute them to any cause, or measure change over time.
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