How Icioola computes its ratings
Your priorities are ranked, then converted into weights by the ROC method (rank-order centroid): the first criterion weighs markedly more than the last, without you having to drag any slider.
A weak point cannot be bought back
Criteria are combined by geometric mean, not arithmetic. A town that excels everywhere except on safety does not offset that hole with its strengths — this is the choice that separates Icioola from an additive score, where everything can be redeemed.
Budget and commute are filters, not averages
If a town exceeds your budget or your maximum commute, it is excluded, not penalised. We tell you how many towns were excluded, and why.
Against towns of similar size
The A–E grades compare each town with others of equivalent size: a village is not judged on the amenities of a metropolis. Stratum thresholds are continuous — no cliff edge at 10,000 or 50,000 inhabitants.
Where the thresholds sit
The grid is fixed and cuts France into five equal parts. It does not adjust itself: a town can only gain a letter if another loses one.
- A — the top 20% among towns of comparable size (5,215 towns)
- B — between the top 20% and the top 40% (5,214)
- C — the middle fifth (5,215)
- D — between the top 60% and the top 80% (5,214)
- E — the bottom 20% (5,215)
Five near-equal counts across 26,073 ranked towns: that is what checks these really are fifths, rather than asserting it.
The score out of 100 is not a school mark
It is a different scale and reads differently: a non-compensatory geometric mean whose French median sits at 45.4. Observed values run from 7.6 to 82.7. A town at 48 is therefore not "below average" — it is above half the country, which is why it can carry a B badge without contradiction.
Measured markers: 10% of towns fall below 30.5, a quarter below 37.3, three quarters below 53.6, and 10% exceed 60.8.
What never enters the calculation
The share of social housing, places of worship and the mayor's political affiliation are excluded from scoring, by explicit choice. An automated test verifies at every build that none of this data can slip into the engine.
When data is missing
A criterion without data receives a neutral score — neither bonus nor penalty — and the real coverage of each criterion is published on the French Data & licences page.
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