Loading approved evidence
Retrieving and verifying the requested analytical release. Result data loads before optional map boundaries and source checks.
Your filters and release stay in the address. Navigation remains available.
Retrieving and verifying the requested analytical release. Result data loads before optional map boundaries and source checks.
Your filters and release stay in the address. Navigation remains available.
SOCIAL FACTORS · ADJACENT DECILE GROUPING V3
Compare deprivation and education deciles with continuous scores, using the same injury collisions, motor mileage and assessment rows.
Adaptive adjacent grouping · research version v3 · no incremental gain
In each annual assessment, training-only geographic validation selected complete pooling of income, employment and education deciles. The resulting model has the same predictions as the baseline. This tests predictive usefulness; it does not establish equal underlying risk across deciles.
No predictive factor promoted. Outcomes from 2023–2025 had already been inspected. This exploratory experiment does not justify deploying a deprivation or education rating factor. Groupings apply to the authority study; no LSOA frequency model is available.
133 ENGLISH AUTHORITIES · MODEL TRAINED THROUGH 2024
1–10
1 band · decile 1 is highest deprivation / no qualifications1–10
1 band · decile 1 is highest deprivation / no qualifications1–10
1 band · decile 1 is highest deprivation / no qualificationsOriginal source deciles remain 1–10. Income and employment use their historical deprivation editions; education uses 2011 Census no-qualifications share. These are custom authority quantiles, separate from official LSOA deciles.
| Original decile | Learned band | Adaptive relative rate | Refit 95% range | Ten-decile relative rate | Next boundary retained |
|---|---|---|---|---|---|
| 1 | 1–10 | 1.000 | 1.000–1.000 | 1.149 | 1.0% |
| 2 | 1–10 | 1.000 | 1.000–1.000 | 1.109 | 0.5% |
| 3 | 1–10 | 1.000 | 1.000–1.000 | 1.025 | 0.5% |
| 4 | 1–10 | 1.000 | 1.000–1.000 | 0.977 | 0.0% |
| 5 | 1–10 | 1.000 | 1.000–1.000 | 1.000 | 0.5% |
| 6 | 1–10 | 1.000 | 1.000–1.000 | 1.092 | 0.5% |
| 7 | 1–10 | 1.000 | 1.000–1.000 | 1.137 | 0.0% |
| 8 | 1–10 | 1.000 | 1.000–1.000 | 1.049 | 1.0% |
| 9 | 1–10 | 1.000 | 1.000–1.000 | 1.291 | 0.0% |
| 10 | 1–10 | 1.000 | 1.000–1.000 | 1.331 | — |
Boundary retention repeats cutpoints, grouping selection and fitting. The training population and score cutpoints therefore vary across refits. It is a stability measure, not a significance test. 199 of 199 paired regional resamples completed.
| Feature | Vintage | Deciles | Authorities | Training collisions | Billion miles | Support |
|---|---|---|---|---|---|---|
| Income deprivation | 2015 | 1–10 | 133 | 195,416 | 479.50 | Pass |
| Income deprivation | 2019 | 1–10 | 133 | 258,041 | 705.91 | Pass |
| Employment deprivation | 2015 | 1–10 | 133 | 195,416 | 479.50 | Pass |
| Employment deprivation | 2019 | 1–10 | 133 | 258,041 | 705.91 | Pass |
| No qualifications | 2011 | 1–10 | 133 | 453,457 | 1,185.42 | Pass |
| Assessment fold | Income bands | Employment bands | Education bands | Social coefficients |
|---|---|---|---|---|
| temporal-2023 | 1–10 | 1–10 | 1–10 | 0 |
| temporal-2024 | 1–10 | 1–10 | 1–10 | 0 |
| temporal-2025 | 1–10 | 1–10 | 1–10 | 0 |
| spatial-East Midlands | 1–10 | 1–10 | 1–10 | 0 |
| spatial-East of England | 1–10 | 1–10 | 1–10 | 0 |
| spatial-London | 1–10 | 1–10 | 1–10 | 0 |
| spatial-North East | 1–10 | 1–10 | 1–10 | 0 |
| spatial-North West | 1–10 | 1–10 | 1–10 | 0 |
| spatial-South East | 1–10 | 1–10 | 1–10 | 0 |
| spatial-South West | 1–10 | 1–10 | 1–10 | 0 |
| spatial-West Midlands | 1–10 | 1–10 | 1–10 | 0 |
| spatial-Yorkshire and The Humber | 1–10 | 1–10 | 1–10 | 0 |
Six models use the same 399 authority-year assessments in 2023–2025. Lower deviance is better. A positive gain means the model improves on the baseline. All fits use a mileage offset; rates and absolute error are per 100,000 all-motor vehicle-miles.
| Model | Deviance | Gain vs baseline | Observed / expected | Predicted rate | Absolute rate error |
|---|---|---|---|---|---|
| Baseline | 8,810.4 | 0.00% | 1.037 | 0.03387 | 0.00497 |
| Continuous · linear | 7,844.3 | +10.97% | 1.030 | 0.03410 | 0.00468 |
| Continuous · smooth | 7,970.8 | +9.53% | 1.028 | 0.03416 | 0.00480 |
| Ten deciles | 8,129.1 | +7.73% | 1.027 | 0.03420 | 0.00487 |
| Fixed quintiles | 8,142.2 | +7.58% | 1.026 | 0.03421 | 0.00486 |
| Adaptive adjacent bands | 8,810.4 | 0.00% | 1.037 | 0.03387 | 0.00497 |
The 0–0% percentile range against baseline reflects a concentration of bootstrap selections at exactly the same baseline model. It is not certainty that social effects are zero, and these post-selection ranges are exploratory.
The fixed-quintile comparison merges 1–2, 3–4, 5–6, 7–8 and 9–10. Adaptive merging is selected for geographic transfer inside training data; it may sacrifice same-authority future-year performance. Every comparator is reported, with no switch to whichever assessment result looks best.
| Comparator | Temporal gain | Refit 95% range | Geographic gain | Replacement supported? |
|---|---|---|---|---|
| Baseline | 0.00% | 0.00% to 0.00% | 0.00% | No |
| Continuous · linear | -12.32% | -26.28% to +2.77% | +4.17% | No |
| Continuous · smooth | -10.53% | -39.13% to +13.53% | +11.12% | No |
| Ten deciles | -8.38% | -48.93% to +3.51% | +28.08% | No |
| Fixed quintiles | -8.21% | -20.52% to +6.24% | +7.24% | No |
| Requirement | Result |
|---|---|
| At least 1% pooled gain | Fail |
| Complete paired interval above zero | Fail |
| At least 1% gain in every year | Fail |
| Pooled O/E between 0.90 and 1.10 | Pass |
| Every annual O/E between 0.90 and 1.10 | Pass |
| Positive pooled geographic gain | Fail |
| Positive gain in at least five regions | Fail |
| Absolute rate error no worse | Pass |
| Every selected training band supported | Pass |
| Converged, full-rank selected point models | Pass |
Replacement additionally requires the upper 95% excess-deviance bound below 0.5%, with no deterioration in calibration or absolute error. A merged pair is not proof of equivalence.
| Year | Continuous · linear | Continuous · smooth | Ten deciles | Fixed quintiles | Adaptive adjacent bands |
|---|---|---|---|---|---|
| 2023 | +5.70% | -7.95% | +0.33% | +1.74% | 0.00% |
| 2024 | +11.57% | +11.38% | +10.02% | +10.88% | 0.00% |
| 2025 | +14.17% | +20.29% | +10.95% | +8.80% | 0.00% |
| Held-out region | Areas | Adaptive gain vs B | Ten-decile gain vs B | Quintile gain vs B | Adaptive O/E |
|---|---|---|---|---|---|
| East Midlands | 8 | 0.00% | -39.80% | -8.35% | 1.199 |
| East of England | 11 | 0.00% | +12.18% | +14.00% | 1.314 |
| London | 33 | 0.00% | -83.07% | -20.15% | 1.244 |
| North East | 10 | 0.00% | -87.27% | -75.23% | 0.832 |
| North West | 22 | 0.00% | -63.65% | -34.26% | 0.977 |
| South East | 18 | 0.00% | +3.45% | +7.87% | 1.174 |
| South West | 7 | 0.00% | +8.12% | +15.11% | 1.181 |
| West Midlands | 12 | 0.00% | +11.44% | +22.81% | 1.102 |
| Yorkshire and The Humber | 12 | 0.00% | -46.15% | -3.23% | 1.052 |
Geographic baseline O/E is 1.152; adaptive O/E is 1.152. Pooling does not resolve omitted transport context or all calibration problems.
| Number of bands | Income deprivation | Employment deprivation | No qualifications |
|---|---|---|---|
| 1 | 196 / 199 | 197 / 199 | 196 / 199 |
| 2 | 0 / 199 | 0 / 199 | 0 / 199 |
| 3 | 2 / 199 | 2 / 199 | 0 / 199 |
| 4 | 0 / 199 | 0 / 199 | 0 / 199 |
| 5 | 1 / 199 | 0 / 199 | 1 / 199 |
| 6 | 0 / 199 | 0 / 199 | 2 / 199 |
| 7 | 0 / 199 | 0 / 199 | 0 / 199 |
| 8 | 0 / 199 | 0 / 199 | 0 / 199 |
| 9 | 0 / 199 | 0 / 199 | 0 / 199 |
| 10 | 0 / 199 | 0 / 199 | 0 / 199 |
There are only nine independent regional blocks. These 199 exploratory resamples provide limited tail precision. All failures are retained in the downloadable record. 0 selected bootstrap designs and 108 comparator designs were rank deficient; they remain in the disclosed analysis using the fixed numerical ridge.
Inner tuning measures geographic transfer. The outer annual tests measure future-year prediction. Seven penalty ratios from zero to the fully merged endpoint were frozen before fitting; this experiment does not rule out every possible grouping or modelling approach.
| Penalty ratio | Social coefficients | Inner deviance | Change vs best eligible | Selected? |
|---|---|---|---|---|
| 1 | 0 | 3,975.2 | 0.00% | Yes |
| 0.3 | 9 | 4,452.3 | +12.00% | No |
| 0.1 | 21 | 4,805.6 | +20.89% | No |
| 0.03 | 25 | 5,237.0 | +31.74% | No |
| 0.01 | 26 | 5,371.0 | +35.11% | No |
| 0.003 | 27 | 5,418.7 | +36.31% | No |
| 0 | 27 | 5,439.5 | +36.84% | No |
Lower inner deviance is better. Ratio 1 is complete pooling; ratio 0 is ten separate deciles. The intermediate choices were available to the selection procedure. These scores are from training-only region splits, separate from the outer assessment results above.
A recorded numerical correction makes the fully merged endpoint use the exact baseline fit. This removes tiny optimizer-roundoff boundaries. The first attempt, correction and unchanged selection rules are available below.
LSOA scope: Authority coefficients and groupings do not transfer to neighbourhoods. Credible matched all-road LSOA mileage is still required. Inspect LSOA profiles and exposure gaps.
Computed 2026-10-10. The same finding register supplies this page and the Actuary Lens summary. Earlier v1 and v2 studies remain available.
Read the Actuary Lens summary. Automated browser and mobile visual review were unavailable; calculation, rendering, query validation and publication checks are recorded.