Short version: Life Score reads the trader's daily equity curve, not their headline ROI.
The inputs are the things a snapshot hides — the worst single day, the deepest drawdown reconstructed from the daily returns, how much the daily returns scatter, and how many days the account actually traded. Steady compounding scores high; the same profit taken with wild swings scores lower; a catastrophic day imposes a hard ceiling no amount of profitability can lift.
Two numbers worth knowing before you read anyone's score. Across the copy traders we score, the average sits near 4.5 out of 10, and fewer than 1% score 8 or above. So a 5 is ordinary, not bad; an 8 is genuinely rare; anything below 3 means the curve contains something the headline figures are not showing you.
Full write-up, including the ceiling table and a worked example of a trader with 121% ROI whose curve fell 99.88%: How to read Life Score.