MDF (Minimum Defense Frequency)

Minimum Defense Frequency (MDF) is a GTO concept that calculates how much of your range you need to continue with (call or raise) to make your opponent's bluffs indifferent. MDF = pot / (pot + bet size). If opponent bets pot on the river, MDF = 50%, meaning you must defend at least 50% of your range. Failing to meet MDF means opponent can profitably bluff with any two cards.