Expanded the crosswalk from 3 pairs to 11. Three are chartable. That ratio is the finding.

Pair	SDG	Tier	Grade	Chartable
PM2.5 annual mean	11.6.2	1	PROXY	yes
Intentional homicide	16.1.1	3	PROXY	yes
Municipal waste recycled	11.6.1	3	PROXY	yes
Road traffic deaths	3.6.1	3	BLOCKED	no
Child mortality	3.2.1	3	CONTEXT	no
Maternal mortality	3.1.1	3	BLOCKED	no
Deaths from air pollution	3.9.1	3	CONTEXT	no
Poverty	1.2.1	3	CONTEXT	no
Inadequate housing	11.1.1	2	CONTEXT	no
Built-up area per capita	11.7.1	1	NO-NYC-SOURCE	no
Safely managed drinking water	6.1.1	3	NO-SIGNAL	no

The harness had the exact bug we are building against

First run reported BLOCKED and CONTEXT pairs as “chartable: yes”. The mechanical checks — does it resolve, do units agree, is there overlap — all passed, so the probe waved them through over the top of a human judgment that said these must not share an axis.

Road traffic deaths was the clearest case: marked chartable on a single overlapping year.

Fixed two ways. The human grade now vetoes the mechanical result, and a trend needs at least five overlapping years rather than a shared endpoint. Worth dwelling on, because it is the product’s whole thesis reproduced in our own tooling: every automated check passed, and the answer was still wrong. Units agreeing is necessary and nowhere near sufficient.

Why the eight fail, which is the interesting part

• Age bands — UN counts child deaths under five, NYC’s series is under one. Both are raw counts, so units “agree”. A chart would look perfect and compare different populations.
• Denominators — maternal mortality is per 100,000 live births, not per population, and NYC’s births live in a different dataset. Also NYC publishes pregnancy-associated deaths, a deliberately broader definition.
• Concept — the UN poverty series is the international extreme-poverty line (~$2.15/day). For any US city that is near zero and carries no signal. NYC’s own measure is an order of magnitude higher. Two numbers sharing a name and measuring nothing alike.
• Measure type — UN reports the share of urban population in inadequate housing; NYC’s nearest analogue is a count of hazardous housing violations, which tracks inspection activity as much as conditions.
• No NYC source — built-up area per capita has Tier 1 UN data with city-level slices across countries, and no NYC equivalent found yet.
• Ceiling effect — safely managed drinking water sits at ~100% for the US and would for NYC. Two flat lines at 100 tell an analyst nothing. Excluded deliberately, and written down as such.

The inversion worth showing at the event

Road traffic deaths is blocked by the UN side, not by us. NYC has Vision Zero collision data updated daily, every fatality geocoded. The UN has one modelled estimate from 2021. For the city’s flagship street-safety programme, the international comparison simply does not exist.

That is the argument for city data flowing toward the UN system rather than only the reverse, and it is a better conversation to have with UNSD in the room than another dashboard.