NEW YORK (MainStreet) —  Verizon Wireless (Stock Quote: VZ) is the most reliable wireless carrier in the U.S. according to new study conducted by research group J.D. Power and Associates.

The provider received the highest marks in five of the six regions of the country – everywhere but the North Central region where U.S. Cellular bested Verizon by four points.

Verizon’s competing carrier AT&T (Stock Quote: T), which was the first to offer the popular iPhone, posted poor performances in five of the six regions, placing last in the Northeast, Mid-Atlantic, Southeast, North Central  and West regions. Sprint (Stock Quote: S) and T-Mobile (Stock Quote: DT) tied AT&T for last place in the Mid-Atlantic and Sprint also tied AT&T for last in the Southeast and North Central regions.

T-Mobile, which is hoping to merge with AT&T, had the lowest ranking in the Southwest.  You can view the full sets of scores per region on J.D. Power’s website, which also describes the study that was based on field interviews with 22,110 wireless customers conducted between January and June 2011.

Overall network performance is determined by how often customers experience the following problems: dropped calls, calls not being connected, audio issues, failed/late voicemails, lost calls, text transmission failures, late text message notifications, Web connection errors, email connection errors and slow downloads.

TheStreet Recommends

Network performance issues are measured as problems per 100 network connections (PP100) and a lower score actually reflects fewer problems and better network performance.

J.D. Power found that even though reliability does vary from region to region, users generally reported more problems while placing calls than when messaging or performing data-related activities. 

Overall, problems associated with calling (dropped calls, initial disconnects and audio issues ) averaged 18 PP100 while data-related issues (Web and email connection errors and excessively slow downloads) averaged 16 PP100. Messaging problems, such as transmission failures and late text messages, averaged only 5 PP100.

“Based on the varying degree of consistency with overall network performance, it’s critical that wireless carriers continue to invest in improving both the voice quality and data connection-related issues that customers continue to experience,” Kirk Parsons, senior director of wireless services at J.D. Power and Associates, said in a press release.

He said there is a financial benefit to providing more reliable service since spending increases by an average of $10 per customer among those who have switched from a previous carrier to obtain a better coverage, compared with those who leave for other reasons.

—For more ways to save, spend, invest and borrow, visit