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The study used the EU’s own Digital Services Act transparency infrastructure to produce its findings — meaning any European regulator can now run the same audit.

A single advertisement on Facebook and Instagram reached 1.32 million unique accounts in Ireland — equivalent to 26% of the country’s entire population. That figure, buried in a new academic paper, is a compliance exhibit.

The study, published in the Journal of Behavioral Addictions by researchers led by Dr Elena Petrovskaya at the University of Cambridge, analysed 411 advertisements placed by 88 licensed gambling operators across Meta platforms in Ireland. Its headline finding — that young men were reached 2.3 times more than women — is significant. 

What makes it consequential for the B2B industry is the method: every number in the paper was pulled from the Meta Ad Library, a publicly accessible tool that exists because of the EU’s Digital Services Act. Any regulator in Europe can open a browser and run the same analysis today.

Of the 411 advertisements examined, 91 (approximately 22%) explicitly targeted men only. None of them targeted women specifically. Across the full dataset, 12.6 million men were reached compared to 5.4 million women.

The more important factor is what happened to the remaining 78% of campaigns that set no gender restriction at all. Apparently, even when operators instructed the platform to reach all genders, the delivery algorithm still skewed heavily toward men. The 2.3x ratio is an outcome figure, not a targeting figure. The operators did not commission it, but the platform produced it.

Dr Petrovskaya said: 

‘Not that many adverts directly targeted men to begin with. But even when adverts were set to reach all genders, they still reached that very vulnerable group of young men.’

The age breakdown compounds the concern. The 25–34 cohort accounted for over a third of all unique accounts reached — more than 6.2 million impressions — and advertisements targeting any part of the 25–44 age bracket reached 59.4% of all accounts in the dataset. 

According to the report, in Ireland, men aged 25–34 have a problem gambling rate of 1.3%, against 0.2% for women in the same age group. The algorithm was not targeting vulnerable users. It found them anyway.

The Cambridge team did not need special platform access or leaked data. They used the Meta Ad Library, which Meta must maintain under Article 39 of the Digital Services Act. The library publishes all active and recently closed advertisements on Meta platforms in EU member states, including demographic delivery data — who saw the ad, broken down by age and gender.

On 2 July 2025, the European Commission adopted a delegated act under the DSA giving vetted researchers access to platforms’ internal data (beyond what the Ad Library already provides). The Cambridge study was conducted using the public-facing tool, but the delegated act makes an even more granular version of the same methodology available to national gambling regulators with researcher status.

The implications for enforcement are direct. European gambling regulators have historically been able to assess what operators instructed a campaign to do. They have had no mechanism to assess what the platform’s algorithm actually delivered. The DSA has now created that mechanism, and the Cambridge paper is the proof of concept.

Dr Deirdre Leahy from MTU Cork, a co-author of the study, described the dataset as ‘a baseline for assessing the impact of reforms under the Gambling Regulation Act’ in Ireland. The same baseline logic applies across every EU market where gambling advertising runs on Meta platforms — which is to say, all of them.

The immediate question for operators active in EU markets is whether their current campaign reporting includes delivery-level demographic numbers. 

Standard agency reporting captures impressions, reach, click-through, and conversion. It almost never captures who the platform chose to serve those impressions to, disaggregated by age and gender. That is the gap the Cambridge study has made visible — and the gap a regulator using the DSA Ad Library can now close independently of the operator.

For compliance teams, three actions might follow: 

• First, they can require post-campaign delivery reports from platform partners that include demographic breakdowns. 
• Second, they can assess whether current media-buying agreements allocate any liability for delivery-level compliance failures. 
• Third, they can review campaigns active in wider EU markets against the methodology described in the Cambridge paper, before a regulator does it.

The study’s authors are calling for ‘wider adoption of laws such as the EU Digital Services Act to provide transparency and accountability for advertising by harmful industries.’ In the iGaming context, that is much more than a theoretical recommendation. The infrastructure is already live. The methodology is published. The only question is who runs the next audit.