The share of your equity you actually turn into pot winnings.
It drops by what you lose when forced to fold along the way and what you pay when behind. It goes up with position, suited and connected cards, hands that make the nuts, and heads-up pots, and down OOP, offsuit, with dominated hands, with players behind, and multiway. Example. A4o has more equity than 76s, but it loses on the kicker and pays off more, so its EQR is lower. Exact values only come from a solver, so preflop, decide with the defense charts, which already include this discount.