How the sources work
Every figure here carries a value, a unit, a period, a named source and the date it was retrieved. This page counts them, names the registers behind them, and lists what we tried to read and could not.
The record every figure carries
A number without a date is a number you cannot check. So every figure in every article is recorded with five things, and the article states all five:
| Field | What it means | Example |
|---|---|---|
| Value | The number itself | EUR 75.36 |
| Unit | What it is per, so it cannot be misread as a total | per tonne of CO2e |
| Period | The window the figure applies to | Q1 2026, published 7 April 2026 |
| Source | A named body, not a trade-press summary | European Commission, DG TAXUD |
| Retrieved | The date we read it, so staleness is visible | 2026-10-03 |
All 303 published figures carry a retrieval date. Where a rate is published by a government and we could not reach the primary text, the article names the accessible source it did use and says so.
Which registers the numbers come from
Legal text and official statistics, not summaries of them. A law-firm note or trade-press report is used as a lead to find the instrument, and when it is the only thing available the article says that too.
- EUR-Lex and the Official Journal — EU regulations, including CBAM and safeguard measures.
- The Federal Register — United States rules, notices and effective dates.
- USITC HTS — the United States tariff schedule.
- USTR — Section 301 determinations, exclusion lists and their expiry.
- CBP — entry requirements and processing fees.
- China's State Council, Ministry of Finance and State Taxation Administration — export duty schedules and VAT rebate notices.
- The Shanghai Shipping Exchange — container freight index methodology and readings.
- The Suez Canal Authority — canal periodicals and their effective windows.
- BOE — the Spanish official gazette, for measures published there.
What we tried to read and could not
This is the part a sourcing page usually leaves out. While checking competitors for each article, sources are recorded even when they cannot be opened, and the article notes the gap instead of quietly working around it. Across the article set so far:
| Outcome | What it looked like |
|---|---|
| Paywalled or bot-blocked | A law firm advisory returned HTTP 403 behind a challenge, and a mirrored copy did the same. The advisory's argument reached us through a trade-press quotation, which is attributed as such. |
| PDF that would not parse | A tax advisory published only as a PDF. Recorded on the article as attempted and not read, with a note that it is probably the strongest analysis in that search. |
| Empty response | A parliamentary research study returned HTTP 202 with no body. |
| Definition page absent | An index publisher's definition page returned only its navigation shell, and the English equivalent returned 404. The question it would have answered is stated as open on the article rather than inferred from a sibling document. |
A missing or uncertain figure is safer than a confident guess.Where a gap could not be closed, the article says which question is unanswered and what would settle it, and the reader is told to get it in writing rather than take our reading.
The same record is published as data at /unreadable.json — one entry per host, with the status returned, the date it was tested, what it was wanted for, and what was used instead. It is there so the claim that every figure is traceable can be checked in the direction that is usually left out. The file distinguishes a 412 gateway from a 404, because one means the host refuses automated reads and the other means the path is gone, and the two call for different responses.
It is deliberately not in the sitemap. A sitemap is a list of pages for a search engine, and a JSON payload in one is noise — the link above is how this file is meant to be found. Where a figure in an article rests on a source listed here, the article says so and names what was used instead.
Per-article record
Counts read straight from the published files, so this table cannot drift from what the articles contain.
Where a figure is our own arithmetic
29 of 31 articles declare their information gain as a custom calculation, which means the arithmetic — duty per unit, cost per container, cost per tonne — is ours rather than quoted. Those articles show the working, name the inputs as assumptions, and use the same models as the public calculator, so a figure here can be recomputed rather than taken on trust. 31 of 31 are marked as priced, meaning the cost lands on a buyer's invoice rather than merely indicating a direction.
When a figure changes
Each article carries a date on which it will be re-read against the primary source. When a figure is corrected, the correction is listed on the article itself with its own date rather than being edited in silence. The tracker lists every re-check date.