Every external link in a scanned page is checked on two levels. A link checker stops at the first; the second is where most citation problems live.
Level 1: does the link resolve?
The link is followed, including redirects, to its final destination. Links that return an error, time out, or end on a page that is clearly not the cited one (a homepage, a category page, a generic “not found” page that still returns a success status) are reported as dead or lost sources.
Level 2: does the target still say it?
For links that resolve, CiteRanger compares the claim your page attaches to the link with the content of the target page. A source that still exists but no longer contains the statement, number or fact you cite is reported as a drifted source. Typical cases:
- A statistic on the source page was updated to a new figure
- A product page changed its price or plan names
- A documentation page was rewritten
- A study was replaced by a newer edition at the same URL
What the report shows
For each flagged link: the claim it supports on your page, the link status, and, where a current source confirms the claim, a replacement source. The fix is then a link swap rather than a research task.
Links that are not checked
Internal links to your own site are not part of source validation; any crawler reports those. Links inside navigation and footers are ignored because they are not citations.