Link rot: NYT external links 1996-2019 show ~15-year half-life; 13% of "live" links no longer point to original content

Claim: A 2021 study of New York Times external links from 1996-2019 found a ~15-year half-life of working links, with 13% of "live" links no longer pointing to original content (content drift, not just 404s).

Source: Wikipedia synthesis citing 2021 NYT-link study — https://en.wikipedia.org/wiki/Link_rot

Confidence: Industry-consensus.

Companion: Zittrain et al. (Harvard Law Review 2014) — see Zittrain et al. (Harvard Law 2014): 50% of URLs in U.S. Supreme Court opinions suffer reference rot — 50% of US Supreme Court opinion links + 70% of Harvard Law Review links no longer functional. Older study, larger numbers, similar direction.

The empirical assumption for Candid sourcing: any web citation has a meaningful probability of breaking within 5 years. The defense is not "don't cite the web" — it's capture + quote:

• Capture an archive snapshot at citation time (archive.org Save Page Now, Perma.cc)
• Prefer persistent identifiers: DOIs, ISBNs, government document numbers, regulatory filing IDs
• Quote the source verbatim, don't just link — a ≤25-word direct quote in the citation means the claim survives link death and can be searched in archives. Highest-leverage practice.
• Quarterly automated link-checker; quarterly manual spot-check of high-importance citations
• Date every citation ("as of May 2026" / "retrieved May 2026")

See CANDID REFERENCE: 9-step link-rot mitigation plan — archive on capture, verbatim quote, persistent IDs, quarterly check for the full operational procedure.