Quote · Economist Podcasts
Cockroaches 1, Modi 0: India’s remarkable protests
Where this was said
The Crystal Ball Experiment: Tomorrow's Headlines, Today's Losses
At 15:16 · chapter starts 11:42
Joshua Roberts opens his segment with a thought experiment that is almost too good to be true: what if you had tomorrow's newspaper and could trade on it? Elm Wealth actually ran this experiment, giving 120 participants 15 historical Wall Street Journal front pages from 2008 to 2022 and letting them trade stocks and bonds with up to 50x leverage for each day's session. [1] — Joshua Roberts "Elm Wealth gave 120 participants tomorrow's Wall Street Journal front pages and asked them to trade stocks and bonds. The result was humbli…" 11:40 The results were humbling. Only about half ended up with more money than their $50 starting stake. One in six went completely bust. The average participant turned $50 into just $51. Roberts then explains the mechanics of why: markets don't move on events, they move on the delta between events and expectations. If a great jobs number was already priced in, knowing it in advance is worth nothing — or worse, it triggers a contrarian move. Participants correctly predicted the market's direction only 51% of the time, barely above chance, and even when they were right, they sized their bets poorly — taking far too much risk when uncertain and failing to scale up when confident.
In the Elm Wealth experiment, one in six participants who had access to tomorrow's news headlines lost all of their money trading.
In the Elm Wealth study, participants given tomorrow's headlines started with $50 and on average finished with just $51, barely breaking even despite having advance knowledge.
Markets don't move on events — they move on surprises versus expectations. If a great jobs report was already priced in, knowing it in advance is worthless. Participants in the Elm Wealth study called the market direction correctly only 51% of the time, barely above a coin flip.
