Digital advertising fraud rose significantly in the fourth quarter of 2018, according to the data intelligence and fraud prevention firm Pixalate.

The company’s fourth-quarter 2018 Ad Fraud Update found the U.S. had an average fraud rate of 21%, up from 17% in the third quarter. The company determines the rate of ad fraud by examining invalid traffic across 80 million domains and 1.5 million apps.

The rise in ad fraud may have been attributable to scammers looking to take advantage of higher holiday budgets.

While fraud as a whole was on the rise, there were significant differences between different platforms and companies, depending on the precautionary measures taken.

Websites that utilized ads.txt saw 23% less invalid traffic than sites that did not use it. While the average fraud rate among all platforms was 21%, mobile in-app programmatic advertising saw a higher percentage of fraud, with a 23% IVT rate. 

When looking specifically at programmatic video advertising, smartphone and tablet apps had an IVT rate of 29.6%, with web-based video viewing seeing significantly less fraudulent traffic.

The full report is here.