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  • 19th May 2022

Different frames, fewer games: how betting behaviour is shaped by the way odds information is presented

Imagine you’re deciding to place a bet at a casino. Before putting your money down, you’d probably like to know your chances of winning. You spot some information explaining the odds – “the theoretical average return to player for this game is 93%” – however, the jargon and percentage make it sound a little cryptic. 

Officially, these descriptions are called return-to-player (RTP) statements. The problem is, less than half of people actually understand them and they can be tricky to find. You would be forgiven for thinking the above RTP statement means you have a 93% chance of winning, or that 93 out of every 100 people win something from this game. However, what a 93% RTP really means is that over the many years in a game’s lifetime, for every £1 spent on the game, about 93 pence is paid out in prizes and about 7 pence is lost.

Promotions create further confusion

To make things more complicated, we know high odds aren’t the only incentive to place a bet. Promotions like free spins are a key draw for slot games. Free spins are often salient, accompanied by special effects using colours and sounds. They may mask the true odds of the game and can downplay the riskiness of betting. As a result, people choose to play casino games more where promotions are offered, regardless of how well they understand the game’s odds.

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So what did we do?

Researchers like Dr Philip Newall have shown those who read simpler odds information have a better understanding of their chances of winning and gamble less

Building on the research of Dr Newall and others, we created a slot game and gave participants the option to play using money earned at the start of the study. We measured how well participants understood the odds information, whether this changed the way they played, and what impact – if any – a free spins promotion had. 

For the study, we first randomly allocated 5,311 participants to see one of four different versions of the odds information:

We then randomly allocated around half of all participants (2,608) to receive ten free spins to use at the start of the game.

Finally, the return-to-player group was further divided into two groups where the information was either hidden or more salient – meaning the information varied by where it was listed (start/end of game instructions), the font size (same/larger than other text) and colour (same/different colour to other text). 

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We found that the simplified-loss volatility framing was the best-performing version, increasing understanding of odds and reducing willingness to play.

The simplified loss-volatility framing combined four different elements – so when odds information 1) was simplified to pound (£) terms, 2) emphasised what players could potentially lose, 3) explained game outcomes are volatile, and 4) was made salient, understanding of the odds increased by 3 percentage points (to 14%). The number choosing to play the slot game also decreased by 7 percentage points (to 68%). 

If scaled up, we estimate that better understanding of odds may result in ~184,000 fewer people choosing to play a particular slot game; helping them avoid losses from a game that doesn’t align with their risk preferences.

In contrast, when the industry-standard odds format (return-to-player) was made salient, it increased the misconception that 93% of players will win something by 11 percentage points (to 32%). 

Unsurprisingly, the free spins promotion increased willingness to play by 5 percentage points (to 75%). This also partly counteracted the positive impact the simplified odds information had, i.e. free spins encouraged more people to play the game even when they better understood its odds. 

Finally, we looked at how the findings varied for those at higher or lower risk of experiencing gambling harms. The simpler odds information increased understanding of odds and reduced the decision to play among non-problem gamblers – but not for those experiencing problem gambling. This means problem gamblers may require a more targeted, educational-based intervention to increase their comprehension, which could include correcting specific erroneous beliefs.

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What do these findings mean for policymakers?

Coupled with existing research on what works to increase odds comprehension, we believe there is convincing evidence to recommend:

  1. Return-to-player (RTP) statements should be banned or altered significantly to improve odds understanding.
  2. RTP statements should be replaced by simplified odds descriptions that express outcomes as player losses in pound (£) terms, and emphasise the game’s outcomes are volatile.
  3. It should be mandatory for slot games’ odds information to be listed ahead of all other game information, with distinct formatting.

Want to know more? You can read our full report here.


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