Definition
Plain language
A number that says how surprising a result would be if nothing real were going on — small means the result probably isn't just luck.
As stated in the literature
The probability of observing a test statistic at least as extreme as the one measured under the null hypothesis; small values are taken as evidence against the null, with conventional thresholds like 0.05.
Also called: p value
Why it matters: It gives researchers a standard way to judge whether a result is likely real or could easily be a fluke of chance.
For example, if flipping a coin 20 times gives 18 heads, the p-value tells you how unlikely that lopsided result would be from a perfectly fair coin.
Heard on the show
“… Forking Paths, and by the end you'll understand the fix it proposes: a new statistic, a sibling of the p-value, that can tell you whether a published finding is typical of what the data supports, or was fished …”Episode 196 — AI Agents Reached Opposite Conclusions From the Same Data — and Passed Review