GGB is committed to providing updated news and analysis on our weekly news site,

Making Slots ‘Sticky’

Slot developers and consultants look into the psychology of what makes a player stick with—and return to—a game

Making Slots ‘Sticky’

For nearly four decades, slot machines have maintained their role as the most important revenue-generator for casinos. From when microprocessors were first applied to simple three-reel steppers through all the various incarnations and styles of slot machines, operators and suppliers alike have endeavored to understand what it is that makes a particular slot game successful.

ReelMetrics, a data analytics firm that has helped slot operators and manufacturers solve the game puzzle, calls the effort a quest to create “sticky” slots—programs that cause players to stick with a particular game over others.

“Sticky slots are inherently productive assets with the proven ability to capture and captivate players,” says Nick Hogan, co-founder and CEO of ReelMetrics, which is the world’s largest aggregator of gaming data.

ReelMetrics uses data to show operators how game configurations can lead to slots being sticky as opposed to “slippery,” and to minimize what the company calls the “ricochet effect.”

“Slippery slots are inherently unproductive assets that discourage and deflect players,” Hogan says. “And ricochet is a footfall effect where players spend an inordinate amount of time pinballing from slippery slot to slippery slot until something sticky snags them.”

The quest to solve the puzzle of what makes games stick is ongoing, and confounding to many. New features and game mechanics have rolled out from manufacturers for decades, but according to ReelMetrics chairman and co-founder John Boushy, the number of those innovations that have translated into hit games is relatively small. “One of the biggest problems we’ve had in our industry is that a lot of development in product has really been performed without a great deal of empirical data on the people and behaviors,” Boushy says. “So, we are

really trying to change that.“When you look at the results of what is actually succeeding that’s come out, it’s somewhere in the neighborhood of 25 percent or less… These are failure rates that are way too high.”

The major slot manufacturers have responded by increasingly turning to research and data collection to cull the most from those features and games that do succeed, and use that information to replicate the success.

“The prior behavioral trends of slot players are something that our game designers constantly track,” says Michael Mastropietro, senior vice president of game development for Scientific Games. “Like any form of entertainment, what appeals to players is constantly changing and evolving.

“When making decisions on what mechanics to leverage, we look at what is gaining traction on casino floors regarding our own games and competitors. We leverage proven performers, such as Quick Hit, Dancing Drums, and Lock It Link, as well as evolve ideas that have resonated with players.”

Research into player preferences also involves hands-on experience playing the actual games, says Ian Arrowsmith, senior director of game development for Konami Gaming, Inc.

“I lead a team of game designers at Konami who are all students of the slot industry,” Arrowsmith says. “There isn’t a game in the field our team hasn’t played. They pore over game performance reports, track trends, visit casino sites, and observe what and how players play. Konami also utilizes data gathered from player focus group testing and test banks. In addition, we consider trends and observation from adjacent industries where our parent company actively participates, including amusement, online gaming, and mobile gaming.”

Cody Herrick, director of game design for Ainsworth Game Technology, says scrutiny of games already in the field is among the best ways to discern what features are making players stay at games longer.

“We do conduct player focus groups and internal reviews as well, but a lot of our information about new product development comes from previous product,” Herrick says. “A lot of our research is done on games in the field, how they’re performing now, and trying to learn from that. A lot of our development goes into the behaviors, good or bad, with past products, and researching competitors’ products as well.”

Whether or not the player returns to a specific game, Herrick says, often involves the simplicity of the game. “How easy is it for the player to understand that game?” he says. “We want to learn from that.”

While perhaps not digging as deep as a firm like ReelMetrics, slot developers are leaning on data more and more in determining what makes a successful game.

“Data analytics have been something that game designers have been craving since the beginning,” says Mastropietro at Scientific Games. “Historically, it has been challenging to get a good read on how games are performing. The gaming industry is unusual because the product designers do not interact with the end user but depend on an intermediary, casinos, for feedback. Game designers love any data we can get our hands on, and things are getting better.”

SG just launched SG Connect, a new reporting system that will provide the supplier and its operator customers with valuable player behavioral insights. “These insights will aid us in creating superior games, resulting in increased casino profitability,” says Mastropietro.

“The industry as a whole is now employing more data analytics as well. Casinos want to know not only what is going on in their market but industrywide so they can spot player trends.”

Popular Trends

Game designers and analysts agree that making games simple to understand is one of the most important trends shown to draw players to games.

“There has been a trend which has been occurring for a while now towards increasing immediacy and simplifying wins,” says Mastropietro. “That’s not to say games are simpler. There are numerous ways to present wins to players, but what they won and how they won is much more obvious.”

“Konami designers have a holistic approach to game design, where every component of the game is deemed important to the performance of the game,” says Arrowsmith. “A solid game mechanic with a well-balanced math model provides the bedrock to the game, coupled with stunning graphics and fine-tuned audio to communicate a path to riches for the player. This creates a thrill and anticipation, even when they don’t win big.

“These games communicate some consistent expectations on how the reward experience is delivered, and give repeat players the chance to relive it, or even gain something greater.”

As far as individual slot mechanics, none is more ubiquitous these days than the “hold-and-re-spin” feature first created by Aristocrat for the Lightning Link series, but emulated by just about every other manufacturer. Herrick at Ainsworth, which has created several popular persistent-state titles like Lucky Empress, says players respond to such persistent games because they create a sense of goal-chasing and, when successful, accomplishment.

“The common aspect is anticipation of that big win,” Herrick says. “We’re making sure we’re conveying to the player that anticipation, that moment, that buildup, to when they’re going to get it. Whether we talk about that being a high-volatility game or a low-volatility game, you still want to have that anticipation. That gives the player that feel, that big accomplishment when they win—they earned it.”

“Progressives, and specifically progressive machines with the cash-on-reels and hold-and-re-spin game mechanics, have taken over the premium leased market on casino floors,” comments Rick Eckert, managing director, slot performance & analytics for Eilers & Krejcic Gaming. “This is the popular combination of mechanics that Aristocrat’s Lightning Link skyrocketed into the U.S. market with and continues with Dragon Link and many competitor titles.

“I believe it comes down to the clarity between the games’ payout, or potential payout, to a customer with a simple-to-see-and-follow game mechanic. Persistent play features let the player know that there is an exciting bonus or more wilds waiting for them if they can just play a bit longer, often leading to players digging deeper into their wallet share on that specific game, rather than bouncing around with their gambling budget.”

“These mechanics have become so popular with players because it is very clear what needs to be achieved to win, and what will be won,” says SG’s Mastropietro. “Persistent play,” adds Konami’s Arrowsmith, “suggests a personal investment into an increasing pool of jackpot cash or prizes. This is popular because it allows players to experience and observe some graphic representation of the jackpot cycle, and their part in it.

“Credit collect bonuses like hold-and-spin and stay-and-spin are often easy to understand, with credit amounts displayed directly on the symbols. It’s also common for the prizes to be tallied one-by-one, allowing players to really experience the weight of what they’ve won.”

Playing the Crowd

As slot game mechanics have evolved, game designers have become cognizant of which features appeal to a universal audience, and which appeal to certain groups of players.

“There are certain demographics that like certain kinds of games,” says Ainsworth’s Herrick. “The persistent state-style games coming on maybe draw a different type of player, somebody looking for an advantage. And that goes back to the simplicity of the games, too. You could have a really complicated persistent-state game, and no one’s going to sit there and do math to figure out what state it’s in.

“At the end if the day, it’s good math that’s going to make a good game. And when you have a good game, it works in pretty much all markets across all player segments.”

“The success of a game is ultimately measured by the amount of money a game makes,” says SG’s Mastropietro. “Therefore, high-stakes and core gamblers have more influence on trends than any other demographic by driving performance on casino floors. As a result, the industry is mainly focused on the types of games these repeat players like to play.

“Casual players are drawn to games featuring familiar licensed brands that tend to be less volatile and more geared towards entertainment, such as The Wizard of Oz and Willy Wonka games. Great success is achieved if you can find that sweet spot where the game appeals to both types of players.”

“All of these play mechanics go in a cycle,” comments Mike Trask, director of product marketing and strategy for Ainsworth. “Everyone remembers when different styles of games were the hottest thing in gaming. And here we are, and they’re not. But I’ll bet you go to the casino floor or the trade show later this year, and you’ll start to see that people will find a new twist on them.

“Most stuff in our industry goes in a cycle, and different things get hot for different reasons.”

“It’s like fashion,” says Herrick. “It all comes back around again and gets reinvented for the market today. You could have done a pick feature five years ago and it was low volatility, and maybe it worked then but the players’ tastes have changed. You can still do a pick feature, but you’re going to have to add more volatility now.”

Volatility, in fact, is one of the key factors appealing to another important slot demographic, the traditional slot player—the classic gambler looking for high denominations and high volatility.

“Traditional games will be a steady staple on the casino floor for many years to come,” says Konami’s Arrowsmith. “They may not get as much talk or attention, but there is an enduring appeal.”

Herrick notes that a big portion of Ainsworth’s success has come from the high-denomination, high-volatility game style. “Especially out of our Sydney studio, we have a lot of these game mechanics that are well-known to the player,” he says. “Even though it’s a new game, it still has that feel, that higher volatility, simpler math styles, the free games, concepts like sticky wilds… That player segment is still a big part of the market, and obviously a big part of our game portfolio.”

The Common Denominator

The variety of game styles, game mechanics and appealing slot features may not be as important in creating a “sticky” game as how the game—whatever the style—is configured, and located, according to Don Retzlaf, head of professional services for ReelMetrics.

“The best games are the ones that are configured properly with the right line counts, the right hold percentages, put in the right spots,” Retzlaf says. “Even for the games featuring the top play mechanics, the games have a wide range of performance due to these controllable variables.

“The operator can place some games on the floor that they’re expecting to do two and three times house average, and they have no shot just because of how they’re being set up. These games have a very narrow band for success. And I think the manufacturers are starting to realize that, and they’re starting to want to make configuration recommendations. They just don’t have the data yet, but fortunately, we’ve been able to come up with some configuration options for our clients that take these low-performing games and turn them around, for no cost.

“It’s not as much on the features, whether it’s persistent or hold-and-re-spin. A lot of it is how the games are set up.”

Adds ReelMetrics co-founder and Chairman John Boushy, “There’s been a huge amount of discussion throughout the industry of, ‘should I have a higher hold percentage, lower hold percentage, higher return to player, lower return to player…’ At the end of the day, what the answer is depends upon the overall way the game plays. Because in some situations the best setting is a lower return to player; in other situations, it’s a higher return to player.”

“I just looked at one of the most popular leased games on the floor, where every casino has it,” says Retzlaf. “And the range of outcomes was from less than house average to four times house average. For this one, it was all location-based. A lot of people put these games into poor locations trying to drive traffic, but in this case, the leased game, if you put it in a location that was average or below average, it was barely doing house average.”

Besides configuration and location, the biggest factor in making a game sticky is its winning percentage—not RTP, but the percentage of all play that results in a winning play session. According to Retzlaf, 20 percent is the sweet spot.

“I just finished looking at over 43 million player sessions, taken over a one-year period, and a couple of things jumped out,” Retzlaf says. “Volatility and configuration are the key components of success, and the best games have a player winning session of around 20 percent.

“If they get much higher, then they become a time-on-device game, and it doesn’t resonate very well with the customers.

If they get below 12 percent, the games just have too much volatility, and that leads to multiple poor experiences, and the game loses traction with all those high-frequency players the casinos thrive on. There are some really good games out there, but with a win percentage of 10-12 percent, it just creates a lot of negative experiences. If you lose on that game nine times out of 10, seven times out of eight, you have a lot of negative experiences on those games.”

ReelMetrics has cited research in the past it says demonstrates that most slot floors have too much variety—too many choices equals too many slippery games, the research says.

“We’ve yet to see a single slot floor anywhere in the industry that we would not describe as grossly over-diversified,” says ReelMetrics’ Hogan. “There’s simply too much variety out on the floors, and then to make matters worse, the floors are ridiculously slippery with unproductive assets, outnumbering productive games… What’s happening is that players are spending far too much time transitioning from lousy experience to lousy experience.”

Hogan points to the fact that many casinos have already equaled pre-pandemic slot revenues despite reduced capacity. “Despite the 30-to-50 percent reduction in the total number of active units, we saw unit level revenue gains that were wildly disproportionate—200 to 400 percent lift was by no means unusual.”

He says the company’s research shows “dramatic increases in session duration and far fewer game samplings per trip. Effectively, players found those sticky games very quickly, and they stayed put.”

Slot manufacturers agree that there may be too much variety for players, but some disagree that this fact is causing players to “ricochet” from game to game.

“I do agree that players are being bombarded with too much variety,” says SG’s Mastropietro. “Currently, several hundred games are released each year, with a new game released almost daily. In my first year working at WMS, we released five games a year. Now we are releasing 60-plus, just in Class III.

“I disagree that too much variety is causing players to drift from game to game. I feel the opposite is true. It used to be that five new games would release, and players would play all five. Now, in this game-saturated environment, players are drawn to and focusing on what they know and what is familiar. Because of this, slot brands are becoming more important and powerful. Slot brands, such as 88 Fortunes, Dancing Drums, Lock It Link and Zeus, have huge, loyal followings. Players know what to expect when they play a new title in the Dancing Drums family.”

“The options to the player are vast, but the communication from the game to the player has greatly evolved from five years ago,” says EKG’s Eckert. “Progressives and game mechanics are basically yelling at players from across the casino floor, and once they sit down, the LED button decks have now even evolved to letting players know what they might be getting in return for placing a higher bet, or inversely, what features they lose when betting down.”

“One of the benefits of this new, highly competitive market is that quality is incredibly high, and players’ expectations are rising,” says Mastropietro. “Game hardware, graphics and signage have to be superior to the competition to get noticed.”

“More manufacturers than ever before making more games than ever before,” says Ainsworth’s Trask. “At the same time, though, our 10-year-old high-denom games continue to be the most popular in the country, month after month, year after year. Certainly there’s a competitive market, but when a game sticks, it has its audience.

“Because of the variety and the amount of product being released, and the limited capacity in casinos over the last year, it’s even harder to make something that sticks out. But when you do, I believe the results remain the same. It’s a more competitive market than ever, and it’s hard to get your game played on a casino floor. The sticky games will be there.”

Frank Legato is editor of Global Gaming Business magazine. He has been writing on gaming topics since 1984, when he launched and served as editor of Casino Gaming magazine. Legato, a nationally recognized expert on slot machines, has served as editor and reporter for a variety of gaming publications, including Public Gaming, IGWB, Casino Journal, Casino Player, Strictly Slots and Atlantic City Insider. He has an B.A. in journalism and an M.A. in communications from Duquesne University in Pittsburgh, PA. He is the author of the books, How To Win Millions Playing Slot Machines... Or Lose Trying, and Atlantic City: In Living Color.