Definition
Plain language
Running the same thing twice and getting an exactly identical result, down to the last detail.
As stated in the literature
Full determinism given a fixed seed and action sequence, which permits exact replay of runs for post-hoc behavioral mining rather than re-estimation.
Also called: bit identical
Why it matters: It lets researchers re-examine an old run in new ways without re-running or re-estimating anything, so any difference between two runs must come from the agent, not the dice.
For example, replaying a twenty-season simulation with the same starting seed produces the exact same match results, transfers, and final table, right down to the last decimal.
Heard on the show
“Same seed plus same decisions gives you a bit-identical world, every time.”Episode 245 — Fifteen Models Ran Football Clubs for Twenty Years, and Size Didn't Decide It