Sources and transparency

Every source carries a level from 1 to 5. Level 5 is the legislation itself, the Official Gazette, or the authority that issues the document. Level 4 is another public body or the supplier's own published tariff. Level 3 is a research institute, a university or an established industry report. Level 2 is a reputable marketplace or publication. Level 1 is a single uncorroborated report.

The level is not decorative: a guide cannot claim High confidence without at least one level 4 or 5 source, and validation blocks publication if it tries.

For every source we publish the claim it supports, not just the page title. Knowing that a source is called "Passport" helps nobody; knowing that it establishes the booklet fee at EUR 42.70 does.

Where an amount could vary locally, we verify it against at least two independent sources before presenting it as national.

Institutional pages are reorganised often and links die. At each guide's review we re-check that its sources still respond and still say what we said they said.

When a source disappears we do not leave a dead link: we look for the equivalent, and if none exists we lower the guide's confidence or withdraw the figure.

Source links open in a new tab and carry nofollow, noopener and noreferrer. We cite sources so readers can check us, not to trade ranking signals with them.

We have no commercial relationship with the sources we cite and we do not publish paid links inside guides.