Zittrain et al. (Harvard Law 2014): 50% of URLs in U.S. Supreme Court opinions suffer reference rot

Quote (Zittrain, Albert, Lessig, Harvard Law Review 2014):

"More than 70% of the URLs within the above mentioned journals, and 50% of the URLs within U.S. Supreme Court opinions suffer reference rot."

Source: Harvard Law Review, Zittrain/Albert/Lessig 2014.

Confidence: Verified (foundational academic study).

The 12-year-old finding is still the strongest single argument for URL-design-as-permanence-design. When a Supreme Court opinion's citation infrastructure rots at 50%, that's a measure of how seriously the open web takes URL stability — i.e., not very. The Candid counter-position: slugs are a 10-year design decision, not a SEO tactic. See RULE: Treat URL/slug design as a 10-year decision. Never let a slug change without a 301 redirect..