AP Glossary
WhatIsExpectedValue?
The mathematical average outcome of a bet calculated over infinite repetitions. Positive expected value means the play is profitable long-term; negative expected value means the house has the edge. AP players only take plays where the math is in their favor.
Why It Matters
Why this matters for advantage play
Expected value is the single number that decides whether a play is advantage play or gambling. Every counter, progressive, and threshold ultimately resolves to one decision: play or walk. If you internalize one concept from this glossary, make it EV.
How to Calculate EVCross-Reference
Related terms
Negative EV (-EV)
A situation where the expected mathematical outcome is a net loss. Most slot machines are -EV most of the time. Advantage players avoid -EV plays entirely — the discipline to walk away from -EV is what separates AP from gambling.
Advantage Play (AP)
The practice of using math, observation, and legal strategies to identify and play slot machines with a positive expected value. AP players only play when the numbers are in their favor.
Threshold
The specific counter value at which a machine transitions from house-favored to player-favorable. Run the Slots calculates trigger thresholds for every supported machine based on base game return, counter rates, and bonus values.
RTP (Return to Player)
The theoretical percentage of wagered money returned to players over time. A 95% RTP means $95 returned per $100 wagered on average. RTP above 100% means the math is in your favor.
Frequently Asked
Common questions about expected value
Multiply each possible outcome by its probability and sum the results. For AP, the practical formula is: expected bonus value + expected base return − expected coin-in to trigger. If positive, it's a play.
Absolutely — that's variance. Over a single session or even dozens of sessions, player-favorable plays can lose. The 'long run' that EV describes is hundreds or thousands of trials.
Most proven player-favorable slot plays have edges of 1–8%. That's slim by table-game standards but workable when paired with adequate bankroll and high volume.
Ready to put expected value into practice?
Get access to 204+ machine-specific advantage play guides with exact trigger points, walk-away rules, and floor-walk routes.
Get Access