EV (expected value) in cards is similar to EPA wherein each action or play is either positive or negative (or neutral) depending on a set of known variables. This is quantifiable math as opposed to DVOA/PFF grades which are proprietary and/or subjective.
Example- say the EV of a $50 bet on a particular board, with a particular hand against a range of particular hands your opponent could have, with respect to your implied odds of winning X dollars is POSITIVE, or +EV...if you are playing a mathematically sound game you should always make that bet regardless of outcome. You'll lose the hand a nonzero percentage but if a play is +EV it is the correct move, no matter if you end up winning or losing.
Similar to QB fumble: a QB fumble is always -EPA regardless of who happens to recover it. A bad pass thrown at the defender’s chest is -EPA regardless of whether he intercepts it or it falls to the ground. Using outcomes to determine whether a particular action is positive or negative is inherently flawed analysis, statistically speaking.