Measurement
Uncertainty deduction
An uncertainty deduction reduces the number of credits a project can claim when its measurement is imprecise. The wider the statistical margin around the estimate, the more is taken off, so a project is paid for what it can show rather than its best guess.
The methodology sets how the deduction is calculated. In many, an estimate inside a stated precision carries no deduction, and the claim shrinks as precision falls below it.
It is the practical reason a good sampling design pays for itself. More plots, better stratification and consistent remeasurement narrow the margin, and a narrower margin means fewer credits lost.