THE ACTUARY LENS / MOT EVIDENCE
Does the difference persist?
Compare roadworthiness at the same age and mileage, then test whether the pattern holds across years.
The existing mileage summaries do not establish comparative roadworthiness. No external headline or demonstration data has been substituted for a verified MOT result.
Evidence release: lens-2026-09-23-30b51e970e3eComparison
Awaiting verified evidence
A reviewed raw-test build is needed to compare initial and final failure rates.
The calculation will appear here once its data, coverage and review checks pass. This is an unavailable result, not a zero or evidence of no difference.
Definitions, uncertainty and limits
Coverage starts no earlier than 2022, after DVSA mileage-unit and fuel classification changes. Class 4 is broader than passenger cars. Each vehicle contributes one first completed normal test per year; partial and full retests are excluded from the main rate. This differs from all-test statistics and must not be presented as a direct reproduction without cohort alignment.
Raw and individual-cell intervals use Wilson 95% intervals. Adjusted rates use one frozen reference population and strata with at least 100 vehicles in both fuels in every year. Conservative distribution-free intervals allow a pairwise difference with at least 95% coverage under within-year vehicle independence. Precision does not remove selection bias, make/model confounding or source errors. All intervals are pointwise; exploratory comparisons are not multiplicity-adjusted.
MOT roadworthiness does not measure battery state of health, breakdowns, repairs between tests, software reliability, warranty cost or insurance claim risk. This Lab tests hypotheses; it cannot guarantee a preferred conclusion.
Official DVSA source and data guide ↗