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Ask anyone in this industry for evidence that scent works on a gaming floor and you will get the same number, traced back to a 1995 paper. It ran for 48 hours, at one property, and sits behind a paywall — which means almost nobody quoting it has read it.
There is a better study. It ran on a real casino floor, for twenty days, across 253 slot machines, and it is free to read. It also found something the industry mostly ignores.
The study
Hancock, G. D. (2009). The Efficacy of Fragrance Use for Enhancing the Slot Machine Gaming Experience of Casino Patrons. Master of Science in Hotel Administration, William F. Harrah College of Hotel Administration, University of Nevada, Las Vegas.
The setting. A large United States casino. 253 slot machines across five separate slot areas within the property.
What was measured. Daily coin-in — money actually wagered — over a twenty-day experimental period in June and July 2007, compared against two and a half months of pretest baseline data from the same machines.
The design is the part worth paying attention to. Four fragrances plus an unscented control were rotated through the five locations in 24-hour blocks. That rotation is what makes the study credible: it cancels out the confounds that wreck most floor trials — some banks are simply more popular, more accessible, or hold more preferred machines. By moving every condition through every location, those differences wash out.
The author is explicit that this was built to improve on the 1995 study: twenty days instead of forty-eight hours, disclosed dates, disclosed fragrance components, and controls for special events.
The finding most of the industry skips
The headline is that fragrance in general significantly and positively affected coin-in. That is the sentence everyone would quote.
The more useful sentence is the next one. From the abstract:
"Of the four fragrances, both a refreshing and a soothing fragrance blend with high percentages of natural components, rather than from predominately synthetic sources, significantly and positively affected coin-in."
Four fragrances were tested. Two worked. The two that worked were the ones built with high percentages of natural components. The predominantly synthetic ones did not produce the same effect.
Not the diffusion equipment — that was constant. Not the placement — the rotation controlled for it. Not whether the scent was energising or calming — one of each worked. What separated the fragrances that moved coin-in from the ones that did not was what they were made of.
Why that matters more than the headline
Every scent vendor selling into gaming will tell you scenting increases play. This study is the closest thing the category has to floor-level evidence for that, and it comes with a condition attached that almost nobody repeats: it depended on fragrance quality.
That is worth sitting with if you are comparing proposals. Two vendors can quote the same research, install comparable cold-air diffusion equipment, and specify the same coverage — and if one is dispensing a cheap synthetic blend, this study suggests you should not expect the same result. The hardware is not the variable. The oil is.
It also matches what operators report anecdotally. The most common complaint about inexpensive fragrance is that it smells chemical — and a scent people register as a product rather than an atmosphere is unlikely to be doing the work this study measured.
What the study does not tell you
Being straight about the limits is what makes the rest credible.
We are not quoting a percentage. The abstract reports statistical significance; the detailed results sit in the full text. We would rather point you at the paper than repeat a figure out of context — which is precisely the problem with how the 1995 study gets used.
It is one property. A large US casino, unnamed. One floor, one set of air-handling characteristics, one customer base.
It is twenty days in summer. No seasonal variation, and June and July on a gaming floor are not November.
It measured coin-in on slots. Not tables, not dwell time, not guest satisfaction, not return visits.
"High percentages of natural components" is a description, not a specification. It does not tell you a threshold, and it does not mean synthetic materials have no place in a good fragrance — well-made aroma chemicals are part of virtually every serious formulation. What it distinguishes is a blend built largely from cheap synthetics against one built with substantial natural content.
A second study, measuring something else entirely
Six years earlier, a doctoral dissertation from the same UNLV college measured an outcome this one did not: not what people spent, but whether they engaged with each other. In a controlled comparison, adding an ambient scent to an otherwise identical room produced significantly more social interaction among the people in it.
That one took place in a waiting room on the UNLV campus rather than on a floor, so it establishes a mechanism rather than a result. But it is directly relevant to the hospitality side of a property — bars, lounges, restaurants and the hotel lobby, where the room's job is that people stay in it rather than move through it. What that study found, and what it does not show →
What actually determines whether it works on your floor
The research says the mechanism is real and that fragrance quality is a condition of it. Neither tells you whether a programme will succeed in your building. That comes down to engineering.
Coverage and airflow. Gaming floors are enormous, open and heavily ventilated — air changes are high by design, far higher than a retail space of the same footprint. Fragrance introduced into that volume behaves nothing like fragrance in a closed room, and coverage that would be generous in a lobby disappears on a floor.
Zoning. A property is not one environment. Main floor, high-limit rooms, hotel lobby, restaurants and back-of-house have different expectations and different air handling. Treating them as one zone produces a result that is wrong in most of them.
Ceiling height. Scent disperses in three dimensions. A high-ceilinged floor needs a different specification from a low one at identical square footage, and this is among the most common specification errors.
Continuity. Gaming runs 24 hours. A programme that is right at 9pm and absent at 6am is not a programme — and staff will compensate by turning it up, which makes the peak unpleasant and generates the complaint that gets it cancelled.
The smoke question, honestly
Scent does not solve cigarette smoke. Smoke odour is a ventilation, filtration and source problem — high air exchange, multi-stage filtration, activated carbon, and increasingly a smoke-free policy. Any vendor suggesting fragrance substitutes for that is selling something that will fail visibly.
What scenting contributes, once the air handling is doing its job, is the difference between a floor that smells of nothing in particular and one that smells deliberate. On a property that has gone smoke-free that distinction becomes more visible rather than less — removing smoke does not produce a pleasant environment, it produces a blank one.
What we would specify
Coverage calculated from actual floor volume and air-change rates rather than square footage alone. Separate zones for main floor, high-limit and hospitality. Continuous operation, with intensity as a setting rather than a consequence of the service schedule.
And a fragrance built with real materials rather than to a price point — which, on the evidence above, is not a matter of taste but a condition of the result.
Then a trial on the real floor. No study and no specification tells you how a fragrance behaves in your building, with your air handling, your ceiling heights and your traffic. That is what a seven-day on-site demo is for.
This piece is part of our work in casino scent marketing. Related reading: Air Quality & Fragrance Sensitivity: What Gaming Operators Need to Know, Keeping Scent Consistent Across a 24/7 Casino Operation.