Most marketers still don't have a clear understanding of how programmatic ad buying works even as it attracts a bigger share of budgets, according to a study released today by the Association of National Advertisers and Forrester.

The survey of 153 client-side marketers, which took place between February and March, found that just 23% of respondents understood programmatic buying and use it to execute campaigns. Another 29% said they've heard the term but don't have a clear understanding of it. And 26% said they understand the concept but need to learn more about how to apply it to campaigns. Twelve percent said they were completely unaware of programmatic buying.

Spending on real-time bidding is expected to increase 43.4% percent this year, according to eMarketer. However, a growing awareness that perhaps 30% of digital ads bought are fraudulent is raising questions about programmatic, where much of the fraudulent activity is believed to occur. The study highlights the fact that an industry-wide solution will be difficult to come by since so few marketers understands the process.

"We may have grown up a little too fast," said ANA president Bob Liodice.

Mr. Liodice said the industry needs take action against fraud and, if it doesn't, programmatic growth would suffer. "I do think it will be far less robust in the future as marketers become aware," he said.

The ANA plans to help increase awareness. "It's an issue that we have to address with greater volume, greater noise," he said. "You can rest assured that we will not be receding in our call to action for building a more trustworthy digital supply chain."

Still, the study shows that even the basics of programmatic buying aren't understood by advertisers, which will make it even more challenging to stamp out bad actors in a rapidly evolving market.

"Change is happening at such a rapid pace, it's very difficult to wrap your arms around everything," said Mr. Liodice.