Seat Mii 2015: MOT failure rate for its age
19.1% of 16,223 MOT tests of the Seat Mii first registered in 2015 failed at the first attempt (2019–2024; retests excluded). Against this model's own normal rate at the same ages the index is 100.0 (95% CI 96.5–103.5; 100 = normal for this model at that age): the 2015 build year is no different from other years of the same model at the same age.
| Measure | Value | Unit | Compared with | Years | Tests |
|---|---|---|---|---|---|
| Failed first time | 19.1 | % | all ages tested | 2019–2024 | 16223 |
| Index against this model at the same age (95% CI 96.5–103.5) | 100.0 | index | 100 = normal for this model at that age | 2019–2024 | 16223 |
| Rank among this model's 9 build years | 5 | of 9 | 1 = fails least for its age | 2019–2024 | 16223 |
| Tested in 2024 | 2679 | tests | median 48,289 miles | 2024 | 2679 |
Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · full dataset (v5).
How does the 2015 Seat Mii fail at each age?
Cars built in 2015 were tested at ages 4 to 9 between 2019 and 2024. Each row compares their first-time failure share with what this model normally shows at that age, after allowing for the overall failure level of each test year.
| Age | Tests | Failed, % | 95% interval | Normal for this model at that age, % | Index (100 = normal) |
|---|---|---|---|---|---|
| 4 | 2,742 | 17 | 15.7–18.5 | 16.3 | 104.3 |
| 5 | 2,691 | 17.7 | 16.3–19.2 | 16.9 | 104.8 |
| 6 | 2,689 | 18.1 | 16.7–19.6 | 18.5 | 98.1 |
| 7 | 2,725 | 18.5 | 17.1–20 | 19.6 | 94.7 |
| 8 | 2,697 | 20.7 | 19.2–22.3 | 20.8 | 99.8 |
| 9 | 2,679 | 22.7 | 21.1–24.3 | 22.7 | 99.8 |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 16,223 (initial tests) · Method: normal rate = this model's first-time failure share at that age across its build years (cells of 400+ tests), adjusted for each test year's overall level; cells of 30+ tests, under 500 marked rough · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
What fails most on the 2015 Seat Mii?
The most common failure group on cars built in 2015 is visibility: 6.7 items per 100 first tests, against 6.1 across all build years of the Seat Mii. These counts are not age-adjusted: cars built in 2015 were tested at ages 4 to 9.
| Failure group | Built 2015, per 100 | All build years, per 100 | Items |
|---|---|---|---|
| Visibility | 6.7 | 6.1 | 1,080 |
| Brakes | 5.7 | 7.1 | 922 |
| Lamps, reflectors and electrical equipment | 4.8 | 4.5 | 774 |
| Tyres | 4.6 | 5 | 750 |
| Noise, emissions and leaks | 4.4 | 2.3 | 714 |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 16,223 (initial tests of this build year) · Method: failure items grouped by DVSA's top-level defect groups, per 100 initial tests; groups with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
How does 2015 compare with the years around it?
Among the 9 published build years of the Seat Mii, 2015 ranks 5 (1 = fails least for its age). 2014: index 92.0. 2016: index 108.2.
| Build year | Index (100 = normal) | 95% interval | Verdict | Tests |
|---|---|---|---|---|
| 2012 | 107.5 | 103.5–111.5 | worse | 10,713 |
| 2013 | 105.7 | 102.8–108.6 | worse | 21,297 |
| 2014 | 92.0 | 89.0–95.0 | better | 18,739 |
| 2015 | 100.0 | 96.5–103.5 | no different | 16,223 |
| 2016 | 108.2 | 103.9–112.5 | worse | 13,470 |
| 2017 | 94.9 | 89.4–100.4 | no different | 7,777 |
| 2018 | 94.6 | 87.7–101.6 | no different | 5,080 |
| 2019 | 76.8 | 69.4–84.2 | better (rough estimate) | 3,992 |
| 2020 | 104.9 | 80.7–129.2 | no different (rough estimate) | 559 |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 97,850 (initial tests) · Method: observed failures against those expected for the same model at the same ages, test-year level adjusted; verdict follows the printed one-decimal bound · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
How to cite this page
MOT Risk Index (2026). Seat Mii 2015 MOT statistics (data release dvsa-2024-v2; full dataset motriskindex-families-2024-v5, DOI 10.5281/zenodo.22975051), updated 30 September 2026. motriskindex.co.uk/cars/seat-mii/2015/
How every figure is calculated: methodology. Age, test year and build year are tied together (age = test year − build year), so the test-year level is taken as observed, not estimated.
Other pages for this model
Seat Mii 2012 · Seat Mii 2013 · Seat Mii 2014 · Seat Mii 2016 · Seat Mii 2017 · Seat Mii 2018 · Seat Mii 2019 · Seat Mii 2020 · Seat Mii in Norway · Seat Mii in Finland · Seat Mii in the Netherlands · Seat Mii by postcode area · Seat Mii body, chassis and structure failures · Seat Mii brakes failures · Seat Mii vehicle identification failures · Seat Mii lamps, reflectors and electrics failures · Seat Mii noise, emissions and leaks failures · Seat Mii road wheels failures · Seat Mii seat belts and airbags failures · Seat Mii steering failures · Seat Mii suspension failures · Seat Mii tyres failures · Seat Mii visibility failures