What a consistency rule is
A consistency rule caps how much of your profit can come from a single day. In an evaluation, your best day is compared with your total profit; on a funded account, most firms compare it with the profit since your last payout.
Example: with a 50% rule and $3,000 of profit, your best day can be at most $1,500. If one day made $2,000, you need more profit on other days before you pass or get paid.