Understanding the Return to Player (RTP) Notion and Messages

Slot machines became over the last two decades the most popular casino games, despite being the most non-transparent games of chance. Indeed, the structural characteristics of these games and their inner design are kept secret by slot producers and this secrecy prevents players or experts to retrieve statistical information about those games. The only statistical indicator of a slot game that is either provided with the game or retrieved by statistical methods is the Return to Player (RTP). The RTP is an important indicator, as many players take it as the main criterion of choosing a slot game. However, not all players have a good grasp of the notion of RTP and many of them misunderstand or misinterpret it, and such errors may fuel several misconceptions and irrational myths about slots. This is why the understanding of the RTP became a subject of research in the academic community of problem gambling, where the slot games received utmost attention, as the games of chance with the highest potential of causing their players the development of a problematic gambling behavior.

What is RTP?

In common terms, the RTP is the percentage of the total amounts wagered that a machine pays back over the long run, over all its prizes, and to all its players. Even from this simplistic definition, we can see that the RTP is expressed as an average; however it is not about an arithmetical average, but a statistical one.

For understanding the precise notion of RTP and its nature, we have to have a good grasp of the notion of expected value of a bet (EV), which is a statistical mean of the payout rates of that bet, weighted by their probabilities. Then, the house edge is just the opposite in sign of the expected value: HE = – EV

When we play a slot machine, we actually place a bet, which has its own expected value. The RTP is mathematically expressed as: RTP = 1 – HE.

This formula employs and aggregates all the payout rates of the prizes offered in the game multiplied by their individual probabilities (which are not known if the parametric configuration of that game is not revealed). Thus, the RTP is a statistical average (like EV and HE) and it is just a form of expressing the house edge from the player’s perspective on gains, specifically used for the game of slots.

Why do people misunderstand and misinterpret RTP?

The concept of statistical average is not so complex for a mathematical mind, but it may pose major issues of understanding and especially interpreting in the real life of gambling, for a non-math person. This happens first because it employs the notion of probability, which can be very tricky for those unfamiliar with probability theory.

A second cause is that the notion is used in mixed language (that is, containing both mathematical and non-mathematical concepts and terms), which is predisposed to misinterpretations and semantic conflicts.

Third, the notion of RTP belongs to a mathematical framework that is grounded on the (non-mathematical) concept of randomness, and an inadequate perception or understanding of this complex concept impacts the understanding of all statistical concepts, especially when talking about their application in real life.

Understanding RTP in problem gambling

Problem-gambling research over the last decades recognized slot machines as the games of chance with the highest potential to provoke their players' addiction and in general problematic gambling.

In addition, several risk factors in problem gambling were associated with slot machines. Among them are classical gambling misconceptions, fallacies, and irrational beliefs, among which overestimations of win chances, illusion of control, and the near miss effect.

Misunderstanding and misinterpretation of the RTP submit to these risk factors in the cognitive zone. Given the relationship between the understanding of the RTP and problematic gambling, the form in which the information about RTP is provided by slot producers, operators and media also raises ethical aspects falling within the responsible gambling norms.

All these health, commercial, legal, and ethical aspects have imposed the research of the RTP matter within the academic field of problem gambling.

In-depth research of RTP messages and their understanding

In 2014, a group of researchers from the NatCen Social Research institute in the UK published a wide-scope scientific study dedicated to the RTP messages displayed on the slots machines and how they are understood by players.

The research was commissioned by the Responsible Gambling Trust in a policy context where the Gambling Commission’s regulations require the proportion of total stakes returned in prizes to be displayed on any machine (this regulation is also present in many jurisdictions beyond the UK). The Gambling Commission’s slot machine technical standards require the provision of such information in standard forms, through statements relating to the ‘return to player’ or ‘average payout percentage’. On the other hand, the Gambling Commission considered that players should benefit from greater transparency around the statistical indicators of a game (not only the RTP), and in respect to game features in terms of how they could affect the RTP.

The mentioned research aimed to contribute and align to this policy, by providing practical and useful information about what players do and do not understand about RTP messaging and providing suggestions for improvements.

Setup and methodology of the study

This qualitative study used cognitive interviewing methods for exploring slots players’ understanding and perceived utility of RTP information, involving face-to-face interviews with 25 players.

The sampling was designed to include the diversity of machine players with respect to age, sex, highest qualification, length and frequency of play.

In the interview, participants were shown a set of five different messages on win chances, which are included in different RTP messages:

Message 1 was a ‘basic’ RTP message.

Messages 2a and 2b showed information indicating whether a machine was compensated or random.

Message 3 showed an explanation that the odds of winning are not indicated by the game features or display.

Message 4 showed a variation of an RTP message where the average percentage paid out varied depending on the stake size.

Each message was displayed on a card and shown to the participant in turn. Participants were then asked to think aloud when reading each message. Interviewers then asked a series a series of cognitive probes to explore in more detail their understanding of each RTP message:

- their comprehension of each message;

- whether or not they had noticed the message (or a similar message) when playing machines;

- their view on whether the message was useful to game players or not; and

- their views on whether the messaged could be improved (or made clearer) or not.

Some probes came in the form of a multiple choice question. For instance, for a given basic RTP message:

"This machine has an average percentage payout of at least 90%."

Which of the following best describes what the message means?

90% of people who play this machine will win something.
This machine will give out a prize 9 times in 10.
If you put £1 in this machine you are guaranteed to win 90p.
For every £100 put into this machine about £90 is paid out in prizes.”

Data management and analysis were conducted with a Framework approach.

Results on understanding the RTP messages

The results suggest that current RTP messages are not well understood for a number of reasons, supporting the Gambling Commission’s concerns:

Messages use technical language that does not hold the same meaning for the non-experts as for the industry specialists.

Messages use complex terms that have ambiguous or unclear meaning.

The provision of messages in English adds to difficulties with understanding them for those for whom English is not their first language.

The use of mathematical terms and language such as ‘average’ payout, ‘random’ payout schedule, and the expression of win chance as a percentage assume a level of mathematical literacy that some players do not possess.

There was some evidence suggesting that the current messages are being interpreted by some users as meaning that players are going to win.

Only six participants understood the RTP message as intended, namely that winning was based on chance, that this chance was determined by the machine, and that ‘90 per cent’ referred to the proportion of wagers the machine would pay out over an unspecified period of time. For instance: “Although it has an average payout of at least 90% that doesn’t mean that if you spin the wheel 100 times 90 times out of those you will in, or even that if you put £100 in £90 will come out because it’s random.” Female, 51 +

Perceived utility of RTP messages

The majority of participants qualified the RTP message as unclear and therefore unhelpful. The reasons they expressed for these views were:

They misunderstood the message.
The use of percentages and averages was confusing to those with low levels of mathematical literacy.
The message was considered misleading because:
- It didn’t specify a time period over which the average payout applies; or
- The participants didn’t believe the RTP was 90% as based on their experience or their view that the machines operated at a lower RTP.
They played for fun and enjoyment.
Whether you win or not depends on other factors, such as whether someone has just won the jackpot, how long you play for, how the machine is playing, or how lucky you are.

In addition, those who were skeptical about the RTP message felt it was only displayed because there was a legal requirement to do so.

The participants who misunderstood the original RTP message provided suggestions for improving it and all participants were presented alternative messages, with information ranging from the odds of winning any prize or jackpot to the average hourly loss rate and variations showing the amount of money spent.

Views were mixed in regard to whether these messages would be useful or not and there was no clear consensus over which messages were felt to be the most important or most useful

Learning points and further development

This study provided some useful knowledge that could be further developed to provide enhanced RTP messaging:

Messages should be clear, more direct and use less complex terminology.
Players may not notice or use the RTP messaging. For any kind of responsible-gambling messaging to be effective, the messages have to be visible and players have to understand them, reflect on the information conveyed in the messages and then, hopefully, translate this information into changed behavior.
RTP messages may not influence players’ behavior at all or in the way intended. The wording of messages needs to be carefully formulated and tested to ensure that they influence players behaviors in the ways intended and do not have harmful consequences.

Further interdisciplinary research is of course needed to establish the extent and nature of the RTP misunderstandings, and empirical research is needed to test alternative wordings of RTP messages, to assess their performance in terms of being of interest to players, being correctly understood, and influencing players’ behavior as intended.

Final thoughts

Playing informed is one of the main responsible-gambling norms and the slots RTP messaging falls within this requirement. However, the adequate understanding and interpretation of this information in the players’ side submits to the more complex cognitive dimension of the gambling phenomenon, which is subject to ongoing interdisciplinary research. Empirical studies such as that presented contribute to both shaping an adequate theoretical framework for the problem-gambling prevention programs and supporting gambling regulatory bodies in their missions.