The average fraud rate across all mobile ad networks stands at 15.7%, according to a new report.

Tune has conducted an investigation into the extent of fraud by looking at the data from 24 billion clicks via 700 ad networks.

The research found that 23.3% of ad networks have significant fraud levels of over 20%.

Tune blamed this on firms enabling fraud and short-changing marketers, while other well-meaning companies have paid too little attention to the “sub-publishers” where marketers’ ads run.

Less fraud on top networks

It stated however that over half of the 500+ ad networks “that have significant traction and traffic” have less than 5% fraud, some even at 2% or lower.

It is the rest of the ad networks however that brings the overall percentage up.

In fact, Tune claims that eight ad networks offer 100% fraudulent clicks, installs or views, though the report did not name these companies.

The report identifies the key problem for the good ad networks is the partnerships with other ad networks and sub-publishers.

“Often, ad networks re-broker ad traffic to other ad networks or to sub-publishers,” said Tune Enterprise Data Evangelist Jim Tommaney.

“One ad network is contractually working with other ad networks. This is generally legitimate as networks provide media buying, but questionable or fraudulent traffic can more easily enter the picture.”

You can read the full report from Tune here.