During the 2022 World Cup, gambling advertisements had a "significant" effect on betting activity.

According to the study, which was published in the journal Addictive Behavior Reports, watching a channel with gambling advertisements increased participants' likelihood of betting by 22–33% and their frequency of betting by 16–24%. The authors speculate that the UK's current limitations on gambling advertising may be insufficient in light of these findings. 

Lead author and research associate Ellen McGrane expounded on the results in a Sheffield Phys.org piece.

"During live games, these TV commercials might be acting as potent triggers, encouraging betting even among those who had no prior intention to gamble."

Notably, the "whistle-to-whistle" ban already applies to gambling advertising in the UK. Betting advertisements are limited by the rule to the pre- and post-game times. Only lottery and bingo advertisements are allowed between five minutes prior to kickoff and five minutes following the final whistle. 

This isn't the case in the US, where states impose more lax advertising regulations. This is especially important in light of the recent rise in popularity of sports-focused prediction markets, which usually function (and advertise) outside of state law.

Ads that have been shown to boost total gambling activity
The authors note that other studies have shown that gambling ads are a major motivator for opening a sports betting account, a catalyst for gambling, and a source of need.

By doing this study, they hoped to "fill an important evidence gap" and determine causality in a practical context. 

They specifically sought to respond to the following research question:

"When a live game is broadcast on ITV (television gambling advertisements) as opposed to the BBC (no television gambling advertisements), are more football bets placed during the game (also known as "in-play")?"

In order to do this, researchers recruited men between the ages of 18 and 45 who had the highest frequency of football [soccer] gambling—400 out of 1000 prospective participants—to participate. Before the study started, 396 people gave their consent and finished the baseline survey. 

The study's daily betting surveys were completed by 92% of those individuals, resulting in a final sample of 365.

According to McGrane, "one of our key findings was that this advertising increases the amount of gambling taking place rather than just shifting people between betting platforms."

The authors contend that the study's "rigorous causal design" produces pertinent policy insights despite the non-representative sample.

According to the article:

"While industry-led limitations on television advertising in the UK have decreased the

frequency of such advertising during the "whistle-to-whistle" period, these results show a short-term behavioral reaction to television advertising and point to possible flaws in the limits, especially for the higher-risk groups who were sampled.

Stricter laws could reduce harm to the public.
The authors acknowledge a number of limitations, similar to those of most studies, such as the possibility for recollection bias and the limited generalizability of their findings.

Nevertheless, McGrane reaffirmed that the study's findings suggest that additional advertising limitations could be required to sufficiently safeguard public health.

"A substantial body of evidence indicates that gambling-related harm also increases when gambling participation rises at a population level, indicating that the existing restrictions may not be effective enough."

Advertising regulations are not being tightened, despite the magnitude of this problem. To effectively safeguard individuals who are most vulnerable, stricter regulation of gambling advertising during live sport may be required, especially prior to heavily televised events like the World Cup.