Observe
This is you if you want to read the instrument — the argument, the cities, the global view. Most people start here.
The headline
Paris and Hamburg both scored ~37 / 100. Six years apart, two statistical systems, one number — and that number is not about either city.
The repeated number is the most important fact in the lineage of the Fab City Index — and it is a ceiling, not a convergence. No measured Western metropolis exceeds it when the instrument is single-cell (Economic × City / Region) and the snapshot is taken at one moment in time with no coupling to action: the largest, most diversified metros land at the bound, while scores below it vary enormously — Lyon 34.30, Strasbourg 21.61, 95 % of ~600 French urban areas under 10/100. Fab City Index 3.0 is the instrument built once you accept the ceiling and ask the next question.
Find your way in
The index is one surface of a larger instrument.
Most people arrive in one of three postures. Pick the one that fits and go straight to the surface built for it.
Maintain data
This is you if you run a partner lab or lead a city's data — you connect sources and populate the cells the index reads.
Run a campaign
This is you if your community needs to create data no platform holds — sensing, surveys, matters of concern. The Making Sense model.
What FCI 3.0 measures
A metabolism, not a snapshot.
Generations 1 and 2 of the Fab City Index — Utopies & FabCity Paris (2018), Boeing (2024) — computed a single cell with rigour: Economic × City / Region. Generation 3 extends that single cell into the full four-pillar by five-scale matrix scaffolded by Vivanco (2024–25), aggregates the twenty cells along two axes drawn from the founding Fab City vocabulary, and adds a response coefficient that makes the index dynamic.
FCIt = DIDOt · (1 − PITOt) · ρt
PITO — Products In, Trash Out — is the metabolic signature of a city operating in the linear-extractive mode. DIDO — Data In, Data Out — is the metabolic signature of a city operating in the regenerative-distributed mode. ρ measures action latency: the speed at which an observation produces a fitted, human-approved response at the appropriate governance tier.
Setting all weights to zero except Economic × City / Region and dropping the coupling term collapses FCI 3.0 to the Boeing / Utopies formulation exactly. Hamburg returns ~0.37. Paris returns 0.3758. Same instrument, less resolution.
The four pilots
One UI, four bioregions, honest provenance.
Barcelona is the first attempt at live data ingestion — Metroverse ECI, IAAC fab-lab catchment, Smart Citizen sensor network, Barcelona Open Data Portal. Boston, Santiago and Bali render in the same UI in this prototype with explicit mock-pill labels — the schema is real, the data is provisional.