Methodology

Every figure here is computed deterministically from the official DVSA MOT record, with no scraping, sampling or estimation. If you run the same public files, you should get the same numbers.

Source

All statistics are computed from the DVSA anonymised MOT tests and results dataset, the official record of every MOT test conducted in Great Britain. We use test classes 1 and 2 (motorcycles) only. Nothing is scraped, sampled, or estimated.

Filters

Pass rates count normal tests only. Retests, partial retests and aborted tests are excluded; including them flatters pass rates, since a retest follows a repair. Rows with corrupt fields (a fraction of a percent of the source data) are excluded.

Definitions

Pass: passed first time with no defect rectified at the station.
PRS: pass after rectification: a defect was found and fixed during the visit. We count PRS separately from clean passes.
Fail: failed the test outright.
Failure groups: defects are grouped by the DVSA inspection manual section (brakes, lamps, tyres…). Advisories are not defects and are excluded from failure counts.

Honesty notes

MOT data measures bikes as maintained by their owners, at three-plus years old. It is a reliability signal, not a lab test. Small samples are marked and low-volume models are held to minimum test thresholds before we publish a rate. Make and model names are as recorded by testers, lightly normalised (e.g. "HARLEY DAVIDSON" and "HARLEY-DAVIDSON" are merged).

Questions about the method? The whole pipeline is deterministic from the public dataset; if you recompute it, you should get our numbers.