Study: AT&T, not Apple, is to blame for dropped iPhone 4 calls

Research says AT&T has the highest overall dropped-call rate among major carriers, even versus Verizon's iPhone 4

When AT&T was the sole service provider for the iPhone, both the company and the device garnered criticism for a purportedly high rate of dropped calls. A study by research company ChangeWave suggests that AT&T deserves the lion's share of the blame. The company has the highest rate of dropped calls among the top four mobile providers, whereas new iPhone carrier Verizon has the lowest rate of dropped calls.

These findings, based on responses from 4,068 customers of AT&T, T-Mobile, Sprint/Nextel, and Verizon, may shed some light on why AT&T is eager to sink its claws into T-Mobile. Perhaps the extra infrastructure would give AT&T's service levels a needed boost or at least average out the carrier's overall dropped call rate on paper.

According to the study, AT&T users suffered a 4.6 percent dropped-call rate in a 90-day period. On the other end of the spectrum, Verizon subscribers registered only a 1.4 percent dropped-call rate during the same time period. T-Mobile's dropped-call rate was 2.3 percent, and Sprint/Nextel's was 2.7 percent.

Percentage of overall dropped calls: Verizon vs. AT&T

ChangeWave also compared historical dropped-call rates over 90-day periods between Verizon and AT&T between September 2008 and March 2011. Invariably, Verizon had fewer dropped calls and in fact saw that rate drop from 2.7 percent in September '08 to 1.4 percent in March of this year. AT&T, meanwhile, steadily rose from 3.3 percent in March 2009 to a spike of 6 percent last September before gradually declining to its current rate of 4.6 percent.

Percentage of dropped calls over past 90 days: Verizon iPhone 4 vs. AT&T iPhone 4

ChangeWave has honed in on comparing AT&T subscribers' iPhone 4 experiences to those of Verizon customers. It found that iPhoners on AT&T suffer more than two and a half times as many dropped calls as iPhone users on Verizon: 4.8 percent vs. 1.8 percent.

What's not entirely clear, at least in the data that ChangeWave made public, is why the iPhone call-drop rate on AT&T is 0.2 percent higher than the overall rate or why the iPhone 4 call-drop rate on Verizon is 0.4 percent higher than the average. Perhaps the "death grip" plays a role here? Or maybe the iPhone is more prone to releasing a signal when a mobile connection becomes spotty?

Whatever the case, iPhone users are nearly equally pleased with their devices, regardless of carrier: 82 percent of those on Verizon and 80 percent of those with AT&T said they were very satisfied with their iPhone 4s, which is certainly good news for Apple.

The bad news here is for AT&T. According to ChangeWave, 46 percent of respondents planning to get an iPhone 4 in the future said they planned to use Verizon; only 27 percent said they'd go with AT&T. The other 27 percent said they were undecided.

This story, "Study: AT&T, not Apple, is to blame for dropped iPhone 4 calls," was originally published at Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog. For the latest business technology news, follow on Twitter.


Copyright © 2011 IDG Communications, Inc.