SquareTrade, a firm that sells third party warranties, has issued a report that shows its customers have reported an increased accident rate for their iPhone 4s than iPhone 3GS owners reported when that device was new. The company said it compared data on the first 20,000 warranty customers for each device, and found that iPhone 4s were seeing more cracked displays, and had more accidents in general.

SquareTrade Chart Showing iPhone 4 and iPhone 3GS Failure Rates

The report also stipulated that it has found the iPhone to be, “a very well constructed device, with a non-accident malfunction rate much lower than most other consumer electronics. […] In SquareTrade’s previous study comparing smart phone reliability from November 2008, we found iPhones to be far more reliable than Blackberrys and Palm Treos.”

In other words, even with the increase in malfunctions caused by accidents in iPhone 4, the device still performs better than the other electronic devices for which the company sells warranties.

Also, SquareTrade hasn’t yet looked at Android devices, adding, “It may yet be seen that even with the double glass, the iPhone has an overall failure rate that is still better than the competition.”

Be that as it may, let’s look at the nature of the damage the company found. The first piece of data is that the iPhone 4 broken screen rate is up 82% when compared to the iPhone 3GS. 2.1% of its iPhone 3GS warranty holders reported cracked screens. This compares to 3.9% of its iPhone 4 customers reporting cracked displays.

SquareTrade Chart Showing Accident Type Distribution

Key to this data, however, is that SquareTrade is counting the back of the iPhone 4 as a “screen,” and not just the front of the device, which is the actual display. The company said that 25% of the broken glass claims involved the back of the device, which is made of glass on the iPhone 4, and is metal on the iPhone 3GS.

There are two important factors here: On the one hand, there’s a sharp increase in incidents of screens cracking, but on the other, that incident rate increase is actually lower than the 100% increase in the amount of glass used to encase the iPhone 4.

What that means is that Apple has made a device which by its very nature offers more surface area that can more easily crack than its older designs, while at the same time the aluminosilicate Gorilla glass used by Apple in the new iPhone is less likely to break (which is in direct contrast to SquareTrade’s own stated conclusion).

Should Apple return to a design with a metal back and aluminosilicate Gorilla glass covering the display, accident rates could lessen dramatically.

Which is neither here nor there. The fact is that SquareTrade’s data shows that the iPhone 4 is more prone to accidents than the previous model, but that it’s still better than the competition.

The company specified that its study is based only on data from malfunctions reported directly to the company, and that it did not include any data in any way from malfunctions or other issues reported to and handled by Apple.