The hubbub in the advertising industry has of late been mostly focused on the rise of adblockers. Just as alarming is the scale of fake web traffic schemes. About 11 percent of display advertising impressions are fraudulent, and globally, advertisers will lose about $6.3 billion this year due to this fraudulent bot traffic, according to a 2014 study conducted by the security firm White Ops and the Association of National Advertisers. And publishers who don’t draw much fraudulent bot traffic are losing out to those who do, as ad dollars are inaccurately allocated.

A new study out today by White Ops and Digital Content Next, a trade organization that represents many large U.S. online publishers, dives a bit deeper into the fraudulent traffic industry and offers some best practices on combatting fake traffic, drawn from publishers with the cleanest traffic.

Thirty-two DCN publishers participating in the study, and their bot traffic was significantly lower than the industry average — 2.8 percent versus that 11 percent figure. (DCN didn’t name the specific publishers in the study, but it considers its members “premium” publishers — think big brands like ABC, The New York Times, and National Geographic.) The publisher with the highest bot traffic in the DCN cohort came in at 6.9 percent.

“We want to see an ecosystem in which every site can rise to the cleanliness standard of the DCN publishers detailed in this report,” DCN CEO Jason Kint said in a statement accompanying the release of the study. “At the same time, our members must continue to be diligent as fraud is an evolving problem and trust is earned each and every day.” (Kint was recently on our Press Publish podcast to discuss the advent of adblockers on mobile.)

Bot rates appear to be tied to publishers’ own audience development and traffic-sourcing policies, the study found. Practices such as selling data to third parties or purchasing traffic from outside vendors were associated with those publishers showing higher bot rates. Notable, also, is the finding that publishers with less overall traffic were more likely to have higher sophisticated bot rates.

What’s a bot-battling publisher to do? The study presented some guidelines, including:

— strictly vetting third-party traffic, or choosing not to source traffic from third parties at all, and then continuously monitoring for fraud

— not relying on viewability as the sole measure of whether an impression was from an actual human or just a bot (the DCN study cited two unnamed “top-volume publishers” with bot rates below the DCN average of 2.8 percent that did not bill solely on viewability)

— not retargeting, or limiting retargeting of, visitors using a piece of code that anonymously tracks a visitor who has already left a site (two publishers who do not retarget visitors to their site had an average sophisticated bot rate of 1.8 percent).

The study drew on a dataset of more than 16 billion desktop display and video impressions between June 22 and August 14. You can download a copy of the full report here.