Decision log

Newest first. Record the why, not just the what — this is what makes a past choice reviewable.

2026-09-14 — The human grade vetoes every mechanical check

The pair probe initially reported BLOCKED and CONTEXT pairs as chartable: resolution, unit and overlap checks all passed, so it waved through pairs a human had judged incomparable. Now the grade overrides, and a trend requires five overlapping years rather than a shared endpoint.

Kept as a decision because the pull to let the automated check “win” will recur every time someone adds a pair. Units agreeing is necessary and nowhere near sufficient.

2026-09-14 — Missing denominator years stay empty

There is no ACS 1-year release for 2020, so NYC rates have no 2020 value — on the year homicides spiked. Interpolating would produce a number visually identical to a measured one, in precisely the case someone would quote it. The probe records dropped years explicitly.

2026-09-14 — Comparators are tiered; city-level is the exception, not the rule

URBANIZATION--DOU_CITY gives a genuine NYC-vs-national-city-aggregate comparison across many countries, but only for five indicators — it clusters in gridded-geospatial families and the administrative indicators have no spatial dimension. Tier 1 (city aggregates, ~5 indicators), Tier 2 (urban/rural, ~8, low NYC relevance), Tier 3 (national totals, everything else).

Plan against Tier 3 as the default. An earlier version of this entry recommended city aggregates as the primary framing, generalising from PM2.5 alone; corrected the same day.

Caveat to carry onto any Tier 1 chart: NYC sits inside the US city aggregate, roughly 7% of it.

2026-09-14 — The pair probe does not assign comparability grades

The probe verifies that a mapping still resolves and that units agree. The grade itself stays a human judgment recorded in crosswalk.json. A machine that scores comparability would be confidently wrong exactly where it matters — the waste pair has agreeing units and is still not an apples-to-apples comparison, because NYC counts residential collection and the UN counts all municipal waste.

2026-09-14 — Road safety is out as the headline demo indicator

SDG 3.6.1 returns one observation for the US (2021). Our application used road safety as the worked example. Replacing it with a GREEN-graded indicator from the coverage report; homicide rate and municipal waste recycling are the strongest candidates because NYC publishes closely matching series.

2026-09-14 — Collaboration hub is a fetchable site, not an MCP server

A URL works in every Claude surface with zero setup for collaborators. An MCP connector is richer but each person has to configure it, and it is only available on some surfaces. The site is a prerequisite for the MCP option anyway, so this is sequencing rather than exclusion.

2026-09-14 — Probe harness is stdlib-only Python

Three people on different machines need to run it without a virtualenv debugging session. certifi is used when importable and falls back to the system trust store.

Superseded — peer-comparator framing

Was: compare NYC to peer cities (needs a non-UN source) or to nations? The DOU_CITY finding above gives a third and better answer. Kept for the record.