The Truth Initiative says its anti-smoking message is working, and it has the numbers to prove it.

Leaders from the Truth Initiative surveyed young people and found 77% of those familiar with its campaigns were opposed to smoking.

The study, published in the Journal of Adolescent Health on Tuesday, surveyed about 9,000 young adults between ages 15 and 21 to determine their exposure to the Truth campaign, agreement with common Truth campaign messages, and desire to smoke. The messages measured included independence from tobacco, anti-industry sentiment, anti-social smoking acceptability, anti-smoking imagery, and social movement support.

“We had a theory when we started that we wanted to change some key knowledge and attitudes when related to smoking behavior,” said Elizabeth Hair, VP for the Truth Initiative Schroeder Institute and the study’s lead author.

The study uncovered a three-step process: those aware of Truth ads had stronger anti-smoking attitudes, these attitudes were associated with more support for an anti-tobacco social movement, and social movement support was associated with the decreased intention to smoke.

The most surprising factor was the interest in an anti-tobacco social movement, Hair said. Teens and young adults have shown they’re interested in a social movement after the Parkland students started a gun-reform push this year, but the leaders at Truth weren’t sure that strategy could work for tobacco.

“What we took a chance on was the concept of a social movement because this generation really loves to be cause-based,” Hair said. “Especially for this generation, [a social movement] is a key piece. Having them all engaged and bringing in the entire group and not just having a cessation or quit message, but making this a cause was important. It really did work well for our campaign.”

The study is proving that Truth’s campaign messages and strategies are reaching young people and having an effect on their attitude and behavior. The organization’s campaigns are known for touching on cultural issues and reaching young people where they are, including at events like the MTV Video Music Awards and on mobile devices.

The next step is reaching the remaining 23% who are either already smokers or nonsmokers who are open to smoking. Hair and Truth Initiative COO Dave Dobbins said it’s a matter of continuing the effort and chipping away at the number.

“The more that we can make it not the cool thing, not the rebellious thing, and not the behavior their peers will be engaged in, that’s going to change those who are open to smoking,” Hair said.

“I don’t think you get them all at once,” Dobbins added. “It’s an ongoing, difficult process where every year there’s 5% to 10% fewer, and pretty soon you get the number pretty low. When I started this back in 2000, the number of kids open to smoking would’ve been way more than 23%. We have to chip away and always find a fresh way to talk to young people.”

For others running public health campaigns, the study is a blueprint for how to measure success. Hair said many in public health want to see behavior changes, but measuring changes in attitude can be a great first step to ultimately changing behavior.

Dobbins said public health campaigns don’t need to be well-funded to be successful, it’s just a matter of persistence. Truth has been working against teen smoking since 1999.

“This study in part validates that if you talk to youth where they live, you can have real changes in how they behave,” Dobbins said, “but only if you have sincere dialogue, not if you’re wagging your finger at them.”