iPhone owners make significantly more errors on text entry than those using the other two types of mobile phone keypads, according to a detailed study by User Centric, Inc., a Chicago-based usability consultancy.

The study involved 60 participants who were asked to enter specific text messages and complete several mobile phone tasks. The keyboard types were the iPhone, the hard-key system using a BlackBerry and the "multi-tap" type with a Samsung E300.

Various techniques were used insure a statistically correct result. iPhone owners had used their phone for at least a month.

The key findings were as follows:

1. Text entry speed for hard-key pads and the iPhone was equally fast, however, iPhone owners made an average of 5.6 errors per message while hard-key QWERTY owners made an average of 2.1 per message.

2. iPhone owners also left more errors in their messages, 2.6 versus 0.8 for the hard-key phone owners.

3. There was no significant difference in the error rates for iPhone owners who were experienced or those who were novices. "Despite the correction features available on the iPhone, this data suggests that people who have owned it for a month are still making about the same number of errors as the day they got it," said Gavin Lew, Managing Director.

4. During text correction, it was found that 21 percent of the iPhone owners were unaware of the magnifying glass correction tool.

In further testing, users who were not familiar with either the iPhone or the hard-key types were tested.

5. "Participants who had previously not used either a hard-key QWERTY phone or an iPhone were significantly faster at entering text messages on the hard-key QWERTY test phone than on the iPhone. These participants also made significantly fewer errors on the hard-key QWERTY than on the iPhone," the report said. Participants rated the hard-key system the highest for ease of text messaging.

The types of errors were also looked at.

6. The report concluded that, "Participants made different types of errors on the iPhone and the hard-key QWERTY phones. The majority of errors made on the iPhone involved substituting a nearby letter for the intended letter. However, on the QWERTY phone, participants made more insertion and omission errors than substitution errors."

The principal conclusion was that the iPhone may fall short for those who do heavy text messaging. The problem of persistent hitting the wrong adjacent key was found to be a "troubling" factor.

"The iPhone is a great switch from a numeric phone. But if you’re switching from a hard-key QWERTY phone, try the iPhone in the store first," Mr. Lew concluded.

iPO spoke with Mr. Lew who stated that no external client or organization paid for this research. It was conceived of internally and 100% internally funded by User Centric.