Unit
- Reels: Video slots display simulated reels on a screen, typically 3 to 5 columns, each containing a set of symbols. The reels spin and stop in a random order determined by the random number generator.
- Paylines: These are predefined patterns across the reels that determine winning combinations. Modern slots can have hundreds of paylines, and players can often select how many to activate per spin.
- Symbols: Each position on a reel shows a symbol. Standard symbols pay for matching combinations, while special symbols like wilds and scatters trigger bonuses or multiply wins.
- Random Number Generator (RNG): A computer algorithm that continuously generates random numbers, even when the machine is idle. When the spin button is pressed, the RNG selects the current number, which maps to a specific combination of symbols.
- Denomination: The value of one credit on the machine, often ranging from one cent to one dollar or more. The bet per spin is calculated as credits bet multiplied by denomination.
- Coin-in and Coin-out: Coin-in is the total amount wagered on a machine over a period, while coin-out is the total amount paid out. These are the basic building blocks of slot performance analysis.
- Hold Percentage: The percentage of coin-in that the machine retains as revenue over time, calculated as (coin-in minus coin-out) divided by coin-in. This is the casino's theoretical edge.
- Progressive Jackpot: A jackpot that increases each time a player makes a wager, often linked across multiple machines. A small portion of each bet funds the growing prize.
- Tilt Switch: A sensor that detects if the machine cabinet is opened or tilted, triggering an alert. Though less common in modern video slots, the term persists from electromechanical days.
- Player Tracking: A system that identifies players via loyalty cards and records their play data, including coin-in, time on device, and theoretical win, enabling targeted marketing.
- Return to Player (RTP): The theoretical percentage of all wagered money that a slot machine will pay back to players over time. For example, a 96% RTP means the machine returns 96 cents for every dollar wagered in the long run, with the casino keeping 4% as the house edge. RTP is calculated based on the paytable and symbol probabilities and is typically disclosed to regulators.
- Volatility: A measure of the risk associated with a slot machine, indicating how often and how much it pays out. Low volatility slots provide frequent small wins, while high volatility slots offer larger but less frequent payouts. Understanding volatility helps operators choose machines that match their clientele's preferences and manage bankroll expectations.
- Max Bet Button: A feature that allows players to place the maximum allowable wager with a single press. This typically multiplies the base bet by the maximum number of credits and paylines. In many jurisdictions, playing max bet is required to qualify for the progressive jackpot. Operators should ensure the button is clearly labeled and functions correctly.
- Free Spins: A common bonus feature triggered by landing a specific number of scatter symbols. During free spins, players receive a set number of spins without additional cost, often with multipliers or extra wilds. These features increase player engagement and can significantly boost the machine's theoretical payout percentage, so operators must verify that free spins are accurately tracked in coin-out calculations.
Regulatory Compliance
Standard: Gaming Laboratories International (GLI) standards
All video slot machines must have their RNG certified by an accredited testing laboratory before deployment. The RNG must produce statistically independent outcomes with no predictable patterns. Operators must maintain documentation of certification for each machine on the floor, subject to inspection by gaming authorities.
Quick Revision
- Video slots use simulated reels, paylines, and special symbols to create winning combinations.
- RNGs are the core of game fairness and must be certified by independent labs.
- Denomination and coin-in/coin-out are fundamental metrics for tracking machine performance.
- Progressive jackpots pool player contributions to create large prizes linked across multiple devices.