When the iPhone 4 was revealed, it was obvious that its design was more fragile than the previous generation: If you double the glass panes, the accidental shattering rate will increase too.
According to consumer electronics warranty company SquareTrade, the "aluminosilicate glass seem to crack at least as often as the old glass." Their data shows that 3.9% of all iPhone 4 owners have reported a cracked screen—meaning the front and the back glass panes—within the first four months. On the iPhone 3GS, this percentage was only 2.1%.
These statistics also show that 82% of all iPhone 4 accidents involve shattering glass panes, compared to 76% of the iPhone.
The company says that "at least a quarter of the broken glass claims involved the back screen." I was expecting an even distribution, but this could be easily explained by the fact that many people use iPhone jackets to protect the back of their devices.
However. while SquareTrade concludes that "the iPhone 4 is significantly more prone to physical damage than its predecessor", they couldn't find any connection between cracked backs and cases.
The total percentage of accidents per unit has increased too: From the 2.8% of the iPhone 3GS to the 4.7% of the iPhone 4. That's almost 70%. Perhaps is time for Apple to give up, admit the empirical evidence and update their phone with a more durable material. [SquareTrade via MacRumors]