AP Glossary
WhatIsExpectedValue?
The mathematical average outcome of a bet calculated over infinite repetitions. Positive EV (+EV) means the play is profitable long-term; negative EV (-EV) means the house has the edge. AP players only take +EV plays.
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 meter, counter, progressive, and threshold ultimately resolves to a +EV / -EV decision. 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 meter value or counter level at which a machine transitions from -EV to +EV. Run the Slots calculates trigger thresholds for every supported machine based on base game return, meter 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% indicates a +EV situation.
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, the play is +EV.
Absolutely — that's variance. Over a single session or even dozens of sessions, +EV plays can lose. The 'long run' that EV describes is hundreds or thousands of trials.
Most documented +EV slot plays have edges of 1–8%. That's slim by table-game standards but workable when paired with adequate bankroll and high volume.
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