Builders’ Day is Tue 22 Sep, the morning is single-track demos, and until today we had no demo — a research pipeline and a docs site, neither of which is watchable for ten minutes in a room of forty builders. Now there is one.

Eleven Pairs, Three Charts

Three charts that hold, each carrying its source, vintage, unit and grade on the face of the card. Then the eight that don’t, with the reason each one fails. The blocked ledger is not an appendix — it is the claim.

The screen the whole thing is built around

Municipal waste recycling. NYC at 17.2% against 23.6% for the US in 2018: a six-point gap and an easy headline. Except DSNY tonnage covers residential collection only and the UN definition includes commercial waste, so the two numbers do not cover the same universe.

Same units. Same period. Same apparent shape. Every automated check passes. Only a person reading both definitions catches it — which is the argument for the entire project, in one chart, in about ninety seconds.

Details worth keeping

• The homicide chart breaks at 2020 rather than bridging it, annotated no ACS 2020. The missing denominator is on the face of the chart instead of hidden by interpolation.
• Every card shows its DCID and its NYC dataset id, so any number can be re-derived from the page itself.
• The closing panel is the inversion: NYC has every road fatality geocoded daily, the UN has one 2021 modelled estimate. That is the argument for the evening showcase — city data flowing toward the UN system.

Published as a Claude Artifact and mirrored on GitHub Pages. The Pages copy is public and needs no sign-in, which is what a showcase screen should depend on.