Betteridge’s Law of Headlines
Etymology
Named after the British technology journalist Ian Betteridge, who articulated it in a 2009 post criticizing a speculative headline. The underlying observation predates him and has been attributed to others, so the eponym is a matter of convention rather than sole authorship. The "law" is really a comment on how interrogative headlines dodge accountability.
noun phrase · /BET-er-ij-iz law/
The rule of thumb that any headline ending in a question mark can be answered with the word "no."
What it names
It is a fast filter for hype: a paper that had solid evidence for a claim would simply assert it, so the question mark quietly signals the writer cannot, which makes it a handy reflex when scanning news.
Example
"Is this the breakthrough that ends all disease?" Betteridge’s law says no, and Betteridge is usually right.
Related idea
A question-mark headline is a soft form of clickbait — the question hooks the click while sparing the writer from having to prove the answer.