JD Power asked customers about network performance for voice calls, text messaging and data. Overall network performance was based on 10 problem areas that affect a customer's experience: dropped calls; calls not connected; audio issues; failed/late voicemails; lost calls; text transmission failures; late text message notifications; Web connection errors; slow downloads and email connection errors.
Network performance was measured in problems per 100 network connections, and a lower score reflected fewer problems and better network performance.
The RootMetrics data goes much further in depth and geography, looking at the national capability of networks by the four largest providers as well as their ability at the state level and in 125 metropolitan areas. RootMetrics said it collected 4.6 million data points about network performance during 218,000 miles of driving tests through all 50 states during the last six months of 2013. Testing was also done in 6,300 indoor locations.
For national results, Verizon finished with the top RootMetrics score for network reliability in five of six categories, with AT&T beating out Verizon for the nation's fastest network. Verizon won for overall network performance, network reliability, and for call, data and text performance.
In its report, RootMetrics noted that both Verizon and AT&T at the national level are "head and shoulders above the other networks" with a "large gap" between Verizon and AT&T and Sprint and T-Mobile. On a 100-point overall scale, fewer than 4 points separated Verizon (89.7) and AT&T (86.2) overall, while there was a large gap to the others: Sprint (68.2) finished third and T-Mobile (64.3) finished fourth.
"If you travel throughout the country or are looking for a network that excelled at our broadest-level testing, Verizon or AT&T remain your best options," RootMetrics said.
At the state level, Verizon finished in first place in 46 of 50 states for network reliability in the RootMetrics study, while AT&T won or tied for first in 16 states. Sprint and T-Mobile never took first place in overall performance or network speed in any of the states.
At the metro level in 125 locations, AT&T "clearly outperformed Verizon," RootMetrics said. Especially with network speed, AT&T won or tied in 92 markets, while Verizon won or tied in 26 markets. Even so, Verizon was the most reliable in the metro findings. Meanwhile, T-Mobile had the top speed result in 20 markets, but Sprint never finished first in speed.
RootMetrics commented that T-Mobile's performance "points to a significant dichotomy. While the 'uncarrier' is starting to offer some truly noteworthy speeds at the metro level, its performance drops dramatically at the broad state and national levels. If you are in an urban environment, T-Mobile could be worth a look, but outside of metros, the story is different."
Sign up for CIO Asia eNewsletters.