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Click Fraud by Ad Unit Size: Over 75% of 300x600 Clicks Are Fake

Our recent series of blog posts on click fraud in programmatic has established that click fraud is a growing problem across devices — smartphones, tablets, desktops, and event Connected TVs/OTT — and channels, including video and display.

But within those devices and channels, which ad units are fraudsters targeting most often? Pixalate examined a few of the most common ad units bought and sold via programmatic on desktops, smartphones, and tablets to answer the question.

Smartphone click fraud by ad unit sizes: 480x320 unit targeted most often

When it comes to some of the most popular ad unit sizes on smartphone devices, fraudsters are clearly drawn to one size in particular: the 480x320 unit.


  • Nearly one-in-four (23.4%) of 480x320 smartphone ad units traded via programmatic were fraudulent in April 2017
  • The 320x250 ad unit was the next-most-popular among fraudsters, with a click fraud rate of 8.8%
  • The 320x480 unit (7.7%) and 320x50 unit (7.2%) both had click fraud rates below 10%

Tablet click fraud by ad unit sizes: Fraudsters attack the 480x320 unit

Like with smartphones, the 480x320 ad unit is the most popular among fraudsters on tablets as well. Unlike smartphones, however, the 480x320 unit isn't alone.


  • One-in-four (20.1%) of clicks on the 480x320 ad unit on tablets were fraudulent in April 2017
  • The 320x250 ad unit saw a click fraud rate of 18%, and the 320x50 ad unit had a 14.4% click fraud rate
  • The 320x480 size had lower click fraud rates compared to some of the other most popular sizes, at 7.9%

Interestingly, click fraud rates for the 320x250 and 320x50 ad units were roughly 2x higher on tablets compared to smartphones. However, the click fraud rates on the 320x480 and 480x320 units were roughly equal on both mobile devices.

Desktop click fraud by ad unit sizes: Over 75% of clicks on the 300x600 unit are fraudulent

For three of the most popular desktop ad unit sizes traded via programmatic, over half of the clicks they receive are fraudulent.


  • Over three-in-four (75.6%) of clicks on 300x600 ads were fraudulent in April 2017
  • The 160x600 unit (51.7%) and 728x90 unit (56.8%) saw over half of their clicks prove fraudulent
  • The 320x250 ad unit had a click fraud rate of 42.6%

Click fraud rates across the most popular desktop ad unit sizes were significantly higher than click fraud rates on the most popular smartphone and tablet ad units. Overall, click fraud is a little higher on desktops than it is on mobile devices, but as noted above, it is a growing problem across all devices and screens.

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