A claim is only as strong as the comparison behind it

Does the apparent lead hold up?

Choose two schools and a precise result. Check the claim, find the periods that tell a different story, and keep the evidence behind your conclusion.

The typical result is the median of annual paired differences. All claims refer to published outcomes on this measure, not overall school quality.

Worked example: St Paul’s / Westminster. Enable JavaScript to calculate your own selection.

The claim being checked

“St Paul’s has a higher typical annual result than Westminster.”

A-level grades at A* · 2010–2025

Marginally higher (0.7 pp); the direction depends on the years chosen.

Across 11 matched years in 2010–2025, the median of St Paul’s minus Westminster is 0.7 percentage points. That is under the 1 percentage point we treat as a clear gap. Only 21 of 45 tested periods point the same way and 24 favour Westminster; a clear direction needs at least 60%. Each available year counts equally; this is not a pooled pupil or examination-entry rate.

How verdicts are graded: a verdict needs at least 3 matched years, and with fewer only the values are shown. A typical gap under 1 percentage point, or a direction shared by fewer than 60% of the tested periods, is reported as marginal.

Share of published A-level entries awarded A* in the named examination year.

11matched years
45valid period checks
5years without a matched result

What changes the answer?

The direction changes when the period changes.

21 windows put St Paul’s higher; 24 put Westminster higher; 0 have a zero median. These windows reuse the same historical years. The counts are not probabilities or a confidence score.

A counterexample retaining the most matched years: 2010–2018 · 9 matched years changes the median from 0.7 pp to −0.1 pp.

Strongest positive window · St Paul’s minus Westminster

St Paul’s higher

6.5 pp

2010–2012 · 3 matched years

Strongest negative window · St Paul’s minus Westminster

Westminster higher

−3.9 pp

2014–2016 · 3 matched years

Extremes are shown to expose sensitivity. They must not replace the full-period finding or be presented as a balanced forecast.

Change the years. See the whole pattern.

Read a starting year across to an ending year. Select a cell to inspect its figures. Each coloured cell contains at least 3 matched observations with the same definition.

+ St Paul’s higher− Westminster higher0 equal median· no valid window
Rows: first matched year. Columns: last matched year. Signs use reported values.
Start / end20102011201220132014201520162017201820192025
2010··
2011···
2012····
2013·····
2014······
2015·······
2016········
2017·········
2018··········
2019···········
2025···········

A span may contain gaps. Windows with identical included years are counted once. We never combine different qualification, population or outcome definitions in one window.

Inspect a period

2010–2018 · 9 matched years

St Paul’s minus Westminster: −0.1 percentage points median annual difference.

Matched years: 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018. Years without a matched result inside this span: none.

Figures use the reported precision. Exact median: −1/10. A small signed gap does not establish a difference in underlying unrounded results.

Exact supporting values · source precision retained
School / yearPublished valuePopulation and denominatorStatus and precisionEvidence
St Paul’s School
2010
53.5%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2010, a_starfig:st_pauls_alevel:16
Westminster School
2010
47%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 565Primary0 decimal placesInspect evidence: Westminster School, 2010, a_starfig:westminster_alevel:22
St Paul’s School
2011
52.3%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2011, a_starfig:st_pauls_alevel:17
Westminster School
2011
53%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 552Primary0 decimal placesInspect evidence: Westminster School, 2011, a_starfig:westminster_alevel:23
St Paul’s School
2012
55.6%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2012, a_starfig:st_pauls_alevel:18
Westminster School
2012
49%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 536Primary0 decimal placesInspect evidence: Westminster School, 2012, a_starfig:westminster_alevel:24
St Paul’s School
2013
44.9%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2013, a_starfig:st_pauls_alevel:19
Westminster School
2013
45%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 532Primary0 decimal placesInspect evidence: Westminster School, 2013, a_starfig:westminster_alevel:25
St Paul’s School
2014
47.7%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2014, a_starfig:st_pauls_alevel:20
Westminster School
2014
47%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 573Primary0 decimal placesInspect evidence: Westminster School, 2014, a_starfig:westminster_alevel:26
St Paul’s School
2015
42.1%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2015, a_starfig:st_pauls_alevel:21
Westminster School
2015
49%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 583Primary0 decimal placesInspect evidence: Westminster School, 2015, a_starfig:westminster_alevel:27
St Paul’s School
2016
45.1%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2016, a_starfig:st_pauls_alevel:22
Westminster School
2016
49%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 570Primary0 decimal placesInspect evidence: Westminster School, 2016, a_starfig:westminster_alevel:28
St Paul’s School
2017
46.9%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary1 decimal placesInspect evidence: St Paul’s School, 2017, a_starfig:st_pauls_alevel:23
Westminster School
2017
47%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 469Primary0 decimal placesInspect evidence: Westminster School, 2017, a_starfig:westminster_alevel:29
St Paul’s School
2018
51%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: Unknown / not recordedPrimary / Secondary0 decimal placesInspect evidence: St Paul’s School, 2018, a_starfig:st_pauls_alevel:24
Westminster School
2018
48%A-level post-2010 A*–E · Grade awardsA-level subject entriesDenominator: 460Primary0 decimal placesInspect evidence: Westminster School, 2018, a_starfig:westminster_alevel:30

Wording you can use and verify

Keep the definition, period and limits with the finding. Download the evidence snapshot to retain the current inputs.

St Paul’s School / Westminster School. A-level grades at A*. Share of published A-level entries awarded A* in the named examination year. Period requested: 2010–2025.
On the reported figures, the median annual difference (St Paul’s School minus Westminster School) is 0.7 percentage points across these matched years: 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2025. Graded verdict: Marginally higher (0.7 pp); the direction depends on the years chosen.
The direction reverses for 2010–2018: −0.1 percentage points, using 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018.
Checked every eligible window: 45 unique overlapping windows with at least 3 matched years and a constant definition (constant-definition-v1). These are descriptive checks on the same records, not independent samples or confidence probabilities. Years without a matched result: 2020, 2021, 2022, 2023, 2024. Differences use reported precision; underlying unrounded results may differ. This does not measure teaching quality or predict admissions.
Method: period-check-v1. Evidence version: c42ae164796a207095c0c15d5df6f1b7a1f9abc3dc65b9d38465ffda8d870ea2.

What the record leaves out

Years without a comparable pair: 2020, 2021, 2022, 2023, 2024. A missing or excluded year does not count as evidence for either school.

Inspect missing years, exclusions and definitions
Year / schoolWhy it was not usedRecords
2010 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2010:a-level:total:cb3cab7e
research:st-pauls:2010:six-school-audit:a-level:derived-published-total
2011 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2011:a-level:total:d4ebf945
research:st-pauls:2011:six-school-audit:a-level:derived-published-total
2012 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2012:a-level:total:e174a93e
research:st-pauls:2012:six-school-audit:a-level:derived-published-total
2013 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2013:a-level:total:e8a1d85f
research:st-pauls:2013:six-school-audit:a-level:derived-published-total
2016 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2016:a-level:total:ff5ea676
research:st-pauls:2016:six-school-audit:a-level:derived-published-total
2020 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; assessment-regime exclusion; missing valueresearch:st-pauls:2020:filed-report:a-level---pre-u-combined
2021 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; assessment-regime exclusion; missing valueresearch:st-pauls:2021:filed-report:a-level---pre-u-combined
research:st-pauls:2021:six-school-audit:a-level:derived-annual-information-a-level
2022 · St Paul’ssource disagreement; research observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuefig:st_pauls_alevel:26
research:st-pauls:2022:dfe-ks5-institution-aggregated-results-6187
research:st-pauls:2022:a-level:2025-summary-version
research:st-pauls:2022:six-school-audit:dfe-completion-cohort:a-level
2023 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing value; source disagreementfig:st_pauls_alevel:27
research:st-pauls:2023:dfe-ks5-institution-aggregated-results-6376
research:st-pauls:2023:a-level:2025-summary-version
research:st-pauls:2023:six-school-audit:a-level:derived-annual-information-a-level
research:st-pauls:2023:six-school-audit:dfe-completion-cohort:a-level
2024 · St Paul’ssource disagreement; research observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuefig:st_pauls_alevel:28
research:st-pauls:2024:dfe-ks5-institution-aggregated-results-5755
research:st-pauls:2024:a-level:2025-summary-version
research:st-pauls:2024:six-school-audit:dfe-completion-cohort:a-level
2025 · St Paul’sresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:st-pauls:2025:dfe-ks5-institution-aggregated-results-5471
research:st-pauls:2025:six-school-audit:dfe-completion-cohort:a-level
2010 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2010:dfe-2010-accountability-c30
new:westminster:2010:dfe-2010-accountability-c31
new:westminster:2010:dfe-2010-accountability-c32
new:westminster:2010:dfe-2011-accountability-c37
new:westminster:2010:dfe-2011-accountability-c40
new:westminster:2010:dfe-2012-accountability-c50
new:westminster:2010:dfe-2012-accountability-c53
2011 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2011:dfe-2011-accountability-c29
new:westminster:2011:dfe-2011-accountability-c30
new:westminster:2011:dfe-2011-accountability-c31
new:westminster:2011:dfe-2011-accountability-c32
new:westminster:2011:dfe-2011-accountability-c33
new:westminster:2011:dfe-2011-accountability-c34
new:westminster:2011:dfe-2012-accountability-c51
new:westminster:2011:dfe-2012-accountability-c54
new:westminster:2011:isc:a-level-isc-population
research:westminster:2011:existing-counts-new-westminster-2011-isc-a-level-isc-population
2012 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2012:dfe-2012-accountability-c29
new:westminster:2012:dfe-2012-accountability-c30
new:westminster:2012:dfe-2012-accountability-c31
new:westminster:2012:dfe-2012-accountability-c32
new:westminster:2012:dfe-2012-accountability-c33
new:westminster:2012:dfe-2012-accountability-c34
new:westminster:2012:dfe-2012-accountability-c35
new:westminster:2012:dfe-2012-accountability-c36
new:westminster:2012:dfe-2012-accountability-c37
new:westminster:2012:dfe-2012-accountability-c38
new:westminster:2012:dfe-2012-accountability-c39
new:westminster:2012:dfe-2012-accountability-c40
new:westminster:2012:dfe-2012-accountability-c41
new:westminster:2012:dfe-2012-accountability-c42
new:westminster:2012:dfe-2012-accountability-c43
new:westminster:2012:dfe-2012-accountability-c44
new:westminster:2012:dfe-2012-accountability-c45
new:westminster:2012:dfe-2012-accountability-c46
new:westminster:2012:dfe-2012-accountability-c47
new:westminster:2012:dfe-2012-accountability-c48
new:westminster:2012:dfe-2012-accountability-c55
new:westminster:2012:dfe-2012-accountability-c56
2015 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2015:isc:a-level-isc-population
research:westminster:2015:existing-counts-new-westminster-2015-isc-a-level-isc-population
2016 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2016:isc:a-level-isc-population
research:westminster:2016:existing-counts-new-westminster-2016-isc-a-level-isc-population
2017 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2017:isc:a-level-isc-population
research:westminster:2017:existing-counts-new-westminster-2017-isc-a-level-isc-population
2018 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valueresearch:westminster:2018:a-level-2018-school-subject-counts
research:westminster:2018:isc-shared-a-level-isc-population
2019 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2019:sixth-form-published-equivalent:newsletter
research:westminster:2019:a-level-2019-school-subject-counts
research:westminster:2019:isc-shared-a-level-isc-population
2020 · Westminsterabsent recordNo recorded value
2021 · Westminsterabsent recordNo recorded value
2022 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2022:dfe-ks5-institution-aggregated-results-2911
research:westminster:2022:a-level-school-subject-counts
research:westminster:2022:isc-shared-a-level-isc-population
2023 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2023:dfe-ks5-institution-aggregated-results-3134
research:westminster:2023:a-level-school-subject-counts
research:westminster:2023:isc-shared-a-level-isc-population
2024 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2024:dfe-ks5-institution-aggregated-results-2662
research:westminster:2024:a-level-school-headline-march-2025
research:westminster:2024:a-level-school-subject-counts
research:westminster:2024:isc-shared-a-level-isc-population
2025 · Westminsterresearch observation outside matched schoolwide scope; incompatible definitions; unknown population basis; missing valuenew:westminster:2025:dfe-ks5-institution-aggregated-results-2586
research:westminster:2025:existing-counts-fig-westminster_alevel-32

A-level-only series. IB, Pre-U, mixed qualifications and school-defined combined definitions are excluded. CAG/TAG years 2020–21 are excluded by default; unresolved competing values are retained in the evidence record but omitted here.

Read the comparison rules

Turn the finding into a better question.

Ask the schools for the missing years on exactly this qualification and population basis.

Results do not isolate a school’s teaching contribution or estimate an individual pupil’s admissions chances. Advisers: the worked review shows what a commissioned check of the original publications adds to this free result.

Exactly what this test does

For each starting and ending matched year in your selection, we test the median annual difference using every eligible observation between them. A window needs at least your chosen minimum of three or five matched years and a constant metric, qualification regime, population and outcome definition. Duplicate included-year sets count once. These are consecutive available observations, not necessarily consecutive calendar years.

Three or five years is a declared descriptive rule, not a statistical guarantee. No missing value is imputed. Pandemic-assessed examination results and disputed or incompatible records remain excluded by the existing evidence rules. University outcomes retain their own definitions. Published rounding can affect small differences; the displayed direction is the direction of the reported values.

A shared link reopens the question against the current publication and warns if the evidence fingerprint changed. Downloading a dated evidence copy retains the inputs and the precise specification. A saved brief uses this browser’s storage; it is not an account or an automatic monitoring subscription.

Method: period-check-v1 on the shared calculation policy constant-definition-v1: a median is never taken across a change of qualification, population or outcome definition, here or on the comparison page. Descriptive sensitivity analysis; no causal estimate, significance test or forecast. Full evidence methodology.

Source evidenceOpen full record ↗