The Food and Drug Administration’s anti-smoking campaign has prevented 350,000 teens from becoming smokers, according to an analysis.

Published in the American Journal of Preventive Medicine, the analysis examined the FDA’s The Real Cost campaign over two years. The paper estimated the push saved $31 billion in smoking-related costs for youth, their families, and society overall.

The Real Cost is focused on youth between 12 and 17 years of age who are at higher risk of becoming smokers, like those who have already tried cigarettes or who are likely to experiment. It focuses on the health effects of smoking and losing control due to addiction. The campaign has run on TV, radio, print, web, and social media.

The FDA’s goal was to change the smoking behavior of 300,000 teens via the campaign, said Kathleen Crosby, director of the office of health communication and education at the FDA Center for Tobacco Products.

“We had a bold goal and were able to exceed that goal at every step of the way,” Crosby added. “To reach 350,000 and change their trajectory, not only for their own health, but the health of the nation, is staggering.”

Crosby credited the campaign’s performance to the research and evaluation the FDA performed throughout it. Her tip for other behavioral-change campaigns is to take time to understand the audience and base every ad and message in solid research before adding creative.

The campaign focused on two facets of smoking: loss of control due to addiction and the cosmetic effects of smoking. The resulting ads focused on teens missing time with friends because they needed to smoke and demonstrated how smoking can affect one’s skin or teeth.

“For something like ‘cigarettes cause cancer,’ most teens already believed that,” Crosby said. “So we looked at beliefs where we knew the science was solid, but where kids’ beliefs weren’t there and started hitting those messages really hard.”

The analysis also demonstrated the effectiveness of money invested in anti-smoking and public-health campaigns. The FDA invested nearly $250 million in the first two years of The Real Cost and recouped the estimated $31 billion in savings.

Those savings include the individual cost of cigarettes and medical care, disability benefits, and most frequent sick leave, among other costs. The paper’s authors concluded that the savings — about $128 for every dollar invested, in this case — have potential policy implications for future public health campaigns.

“[In the case of] a child or teen who would’ve gone to smoke, but didn’t, we wanted to find the impact of a lifetime of diverted medical costs,” Crosby said. “The $31 billion far exceeded my understanding of what it really cost when someone is addicted at a young age. You can really understand the cost associated with each individual.”

The Real Cost, which began in February 2014, initially focused on cigarettes, but has been expanded several times. In 2016, the campaign shifted its focus to chewing tobacco, and this year, it expanded again to include e-cigarette prevention. FDA worked with FCB on the campaign.

This study followed an analysis of Truth’s anti-smoking efforts last month. That research also found similar results that the majority of youth exposed to Truth’s anti-smoking campaigns were opposed to smoking.

The FDA is also working to stop youth smoking through regulations and warning letters. This year, the government agency warned e-cigarette makers, like Juul, not to make products that are attractive to or marketed to kids. In April, the FDA went on an undercover nationwide blitz to stop e-cigarette sales to minors, both in brick-and-mortar retailers and online retailers like eBay.