Variance is a statistical concept that describes how widely possible results can be distributed around an expected or average outcome. In online casino games, it can help explain why results can differ significantly over shorter periods, even when the game’s underlying mathematical characteristics remain unchanged.
Variance is particularly useful when discussing online slots. Two slots can have similar theoretical Return to Player (RTP) percentages while distributing their potential outcomes in very different ways. One might produce a greater concentration of smaller winning outcomes, while another may place more of its potential into less frequent, higher-value outcomes.
Understanding variance does not allow you to predict what will happen next. Instead, it provides another way of understanding how a casino game’s possible outcomes are structured.
What Does Variance Mean?
In statistics, variance describes how spread out a set of possible results is around an expected value.
Imagine two hypothetical games with the same average theoretical outcome. In the first game, most individual results are relatively close to that average. In the second, individual outcomes can be much further above or below it.
The second game has greater variance because there is a wider spread between its possible outcomes.
When applied to casino games, this concept can help explain why games with similar long-term mathematical expectations can still produce very different patterns of results.
Variance is therefore about the distribution of outcomes. It does not tell you whether a game is “good” or “bad”, nor does it predict the outcome of an individual spin or round.
How Does Variance Apply to Casino Games?
Casino games have a range of possible outcomes. Some of these outcomes may occur relatively frequently, while others may be much less common.
Variance helps describe how these possible outcomes are distributed.
A game where outcomes are generally concentrated within a relatively narrow range has lower variance than one where there is a much wider range between its potential results.
This concept can apply across different casino games, although the precise mathematics will depend on the rules and possible outcomes of each game.
It is also important to distinguish the mathematical distribution of results from what happens during one playing session. A small number of rounds represents only a limited sample of the game’s possible outcomes.
What Is Slot Variance?
Slot variance refers to the distribution of possible outcomes within an online slot’s mathematical model.
A lower-variance slot generally has a narrower distribution of outcomes. A higher-variance slot has a wider potential spread, which can mean that more of the game’s theoretical return is concentrated in comparatively less frequent, higher-value results.
This distribution can be influenced by the overall design of the slot, including its regular winning combinations and bonus features.
For example, free spins, jackpots, multipliers and other features can account for part of a game’s potential outcomes. However, simply seeing these features in a slot does not tell you its variance. It is the complete mathematical model that determines how potential results are distributed.
What Is a Low-Variance Casino Game?
A lower-variance casino game generally has possible outcomes that are more closely concentrated around its expected value.
In online slots, this can often be associated with a greater concentration of smaller-value winning outcomes compared with higher-variance games.
However, low variance does not mean a game is safer or that a player is guaranteed to receive regular wins. Random results can still produce losing sequences and outcomes that differ substantially from the game’s long-term mathematical expectations.
The term simply helps describe the spread of possible results.
What Is a High-Variance Casino Game?
A high-variance game has a wider distribution of possible outcomes around its expected value.
For an online slot, this may mean that a greater proportion of its potential is concentrated in less frequent, higher-value outcomes. As a result, individual sequences of spins can differ considerably from the game’s theoretical long-term average.
High variance does not mean that a large win is guaranteed to happen eventually. It also does not mean that a game becomes more likely to produce a large result after a sequence of losing spins.
Variance describes the distribution of possible outcomes rather than when those outcomes will occur.
How Does the Distribution of Wins Affect Variance?
The distribution of potential wins is central to understanding variance.
Consider two hypothetical slots that have the same theoretical long-term return.
The first game distributes more of its potential through numerous smaller-value winning outcomes. Although individual results can still vary, much of its potential is concentrated within a narrower range.
The second game places more of its potential into less frequent but larger-value outcomes. This creates a wider spread between the different possible results.
The second game would therefore generally have greater variance.
This distinction helps explain why two slots with similar headline statistics can produce very different playing experiences. Their theoretical long-term returns may be similar, but the way potential outcomes contribute towards those returns can differ significantly.
Why Can Short-Term Results Differ So Much?
Variance is one reason individual casino sessions can look very different from long-term theoretical figures.
A relatively small number of spins or rounds only represents a tiny sample of all the possible results within a game’s mathematical model.
If a game has high variance, short-term results can potentially be particularly far removed from its theoretical average because its outcomes are more widely distributed.
This does not mean that the game must subsequently compensate for those results.
For example, a sequence of losing spins does not mean a larger win must occur soon to “balance” the game. Previous random outcomes should not be treated as a reliable indication of what will happen next.
Does Variance Affect RTP?
Variance and RTP are related to a game’s mathematics, but they describe different things.
RTP, or Return to Player, represents the theoretical proportion of stakes that a game is designed to return to players over a very large number of plays. Variance describes how widely the potential outcomes contributing towards that theoretical return can be distributed.
This means two games can have the same RTP but very different variance.
For example, two hypothetical slots could both have a 96% theoretical RTP. One could distribute more of its potential through relatively frequent smaller outcomes, while the other could concentrate more of its potential into less frequent, higher-value results.
If you want to explore the long-term percentage in more detail, our Casino RTP – What Is Return To Player? guide explains what RTP represents, how the percentage works and why it should not be interpreted as the return from an individual playing session.
For a broader comparison of these different concepts, RTP, Variance & Volatility: How to choose a slot that’s right for you looks at how the three measurements can help describe different characteristics of an online slot.
Variance vs Volatility: What’s the Difference?
Variance and volatility are closely related terms, and they are sometimes used interchangeably when discussing online slots. However, they are not technically identical.
Variance has a specific statistical meaning. It describes how widely possible outcomes are distributed around an expected value.
Volatility is more commonly used as a practical description of how a casino game’s outcomes are likely to be distributed. Slots are often described as low, medium or high volatility to give players a general idea of their mathematical characteristics.
For example, lower-volatility slots are generally associated with more frequent, smaller winning outcomes, while higher-volatility slots tend to have less frequent but potentially larger winning outcomes.
Our guide to What is volatility in online casino games? explores these classifications in more detail and explains what low, medium and high volatility mean.
Variance vs House Edge: What’s the Difference?
Variance and house edge also describe different aspects of a casino game’s mathematics.
House edge describes the casino’s theoretical mathematical advantage over the long term. Variance describes how widely individual outcomes can be distributed around an expected value.
A game can therefore have a relatively low house edge while still having considerable variance in its individual results.
Similarly, knowing the house edge does not tell you exactly how widely results can fluctuate over a short sequence of rounds.
For a closer look at the long-term mathematical advantage built into casino games, read What is house edge and what does it mean?
Can Two Casino Games Have Similar RTP but Different Variance?
Yes. This is one of the most useful examples for understanding why RTP and variance should not be treated as the same thing.
Imagine two online slots that both have a theoretical RTP of 96%.
The first might distribute a relatively large part of its potential through regular, smaller winning combinations. The second could place more of its potential into less frequent bonus rounds and larger-value combinations.
Their theoretical RTP can remain the same even though the distribution of their possible outcomes is very different.
This also demonstrates why an RTP percentage alone cannot fully describe how a casino game is designed.
How Can Bonus Features Influence Slot Variance?
Bonus features can form part of the way a slot distributes its possible outcomes.
For example, a game might place a significant proportion of its potential into free spins, multipliers, jackpots or Hold & Win features. If some of the game’s higher-value potential is concentrated within less frequently triggered features, this can contribute to a wider distribution of outcomes.
Other games may distribute a greater proportion of their potential through regular base-game combinations.
However, the presence of a large number of bonus features does not automatically make a slot high variance.
The game’s complete mathematical model matters. Two slots could contain similar types of features while distributing their potential outcomes very differently.
Does Variance Tell You How Often a Slot Will Win?
Variance does not provide a precise prediction of how frequently an individual player will receive winning combinations.
It describes the spread of possible outcomes rather than giving a timetable for when those outcomes will occur.
A lower-variance game can still produce a sequence without winning combinations. Similarly, a higher-variance game can produce several winning outcomes close together.
This is why variance should not be interpreted as a prediction tool.
A high-variance slot does not become more likely to produce a large win simply because one has not occurred recently, and previous results do not mean a particular outcome is “due”.
Can Variance Predict Future Casino Results?
No. Understanding variance cannot tell you what will happen on the next spin or game round.
Variance provides information about the statistical distribution of possible outcomes. It can help explain why results may be tightly grouped in one game and spread much more widely in another.
However, it cannot identify which of those possible outcomes will occur next.
This distinction is important when interpreting casino statistics. Mathematical information such as variance, RTP and volatility can help describe how a game is designed, but it should not be used to assume that future random results can be forecast from previous outcomes.
Why Is Understanding Variance Useful?
Understanding variance provides additional context when comparing casino games.
Two slots might have similar RTP percentages, for example, but very different distributions of potential outcomes. Knowing about variance helps explain why their results and overall playing styles may differ despite that similar theoretical return.
Variance can also help explain why short-term results may be significantly different from a game’s long-term mathematical expectation.
Rather than treating variance as a strategy, it is better understood as descriptive information about how possible results are distributed.
Together with RTP, volatility and the game’s rules, it can provide a clearer picture of the mathematical characteristics behind an online casino game.
Understanding Variance at NetBet Casino
When exploring games at NetBet Casino, you may encounter slots and other casino games with very different distributions of potential outcomes.
Where provided, information such as RTP and volatility can give additional context about these mathematical characteristics. A game’s paytable and information section can also explain its available winning combinations, bonus features and other mechanics.
Keep in mind that these figures describe how a game is designed rather than what will happen during your next session.
Previous spins or rounds should not be used to predict future random outcomes, and neither high nor low variance guarantees a particular result.
Casino Game Variance FAQs
What does variance mean in casino games?
Variance describes how widely possible results can be distributed around an expected or average outcome. Higher variance means outcomes can be spread more widely, while lower variance means they are generally more concentrated.
Is variance the same as volatility?
Not exactly. Variance is a statistical concept relating to the spread of possible outcomes. Volatility is commonly used in casino and slot descriptions to communicate the general pattern and intensity of those outcomes. The terms are closely related and are sometimes used interchangeably.
Does high variance mean a slot will eventually pay a big win?
No. High variance means a game has a wider distribution of potential outcomes. It does not mean a large win is guaranteed to happen eventually or that one becomes more likely after a sequence of losing spins.
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