It notes size certainly does matter for mobile ads, as the average click through rate on a full screen interstitial is twice as high on a tablet than on a smartphone.
That's makes sense as the largest smartphone is 5-inches, while tablets go from 7 to 10-inches.
Full screen interstitials on tablets are simply larger and easier to click on.
Absolute value
Yet, conversely, if you look at a specific ad size things are different.
For example a 300x250 ad unit has an average CTR on smartphone of 1.52 percent, compared to 0.94 percent on a tablet.
Again, that makes sense, as a 300x250 ad is going to be taking up more screen size on a smartphone than on the larger tablet.
On Fire
Something that it marginally more interesting, however, is that Velti reckons a 300x250 ad gets higher CTR on a Samsung Galaxy Tab 10.1 (2.39 percent) compared to a similar-sized iPad 3 (1.66 percent).
This may be because more of the iPad advertising is run through Apple's own iAd platform, meaning Velti doesn't get such good data or volumes.
The 7-inch Kindle Fire offers superior CTR in this particular comparison - 3.34 percent.
