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RootMetrics coverage maps show test disparities among mobile carriers

The RootMetrics app for Android mobile devices
The RootMetrics app for Android mobile devices
Google Play Store

Last week we posted an article regarding RootMetrics testing of Baltimore mobile carriers. The testing took place between April 29 and May 5, covered 1215 miles, and consisted of 27,137 tests. In its overall results, RootMetrics declared a tie between T-Mobile and Verizon Wireless for overall performance among Baltimore mobile carriers. After posting last week's article, we decided to take a closer look at the maps RootMetrics posted on-line detailing the performance of each Baltimore mobile carrier. We found an interesting trend emerge, one that made us question the validity of RootMetrics results.

The coverage maps RootMetrics provides on their website to verify the test results appear pretty uniform across each carrier in normal view. After zooming in on the maps, we found a disturbing trend that seemed to fly contrary to RootMetrics' testing methods. All across Baltimore City, many areas for Verizon Wireless, AT&T, and Sprint appear as untested. For some reason, T-Mobile did not suffer this same fate. Their "tested" network appears fairly solid across the map. All three test categories RootMetrics used - Call Performance, Fastest Speed Found, Best Technology Found - showed the same disparity. Was this a monumental glitch in gleaning the results? Could it have been some sinister plot or conspiracy by one of the Baltimore mobile carriers? We needed to find out.

In a conversation with a RootMetrics' spokesperson this week, she verified how the testing was done. As we told you last week, RootMetrics sent four testers to Maryland. Once here, they purchased one phone from each of the four major mobile carriers. They did this to insure the Baltimore mobile carriers would not be aware of their presence, thus garnering a true account of each carrier's signal at any given time. The RootMetrics teams, according to the spokeswoman, then drove to different areas around the Baltimore metro area. This included most of Baltimore, Howard, and Northern Anne Arundel Counties. When testing for each mobile carrier's performance, all four conducted their testing at the exact same time. If that is the case, all the areas tested should show up uniformly on the maps, but they did not. This is where we began questioning the overall results.

As it turns out, the RootMetrics smartphone app we told you about last week is the culprit. The app immediately posts results from individual users to the coverage map. As we were told by our RootMetrics contact, T-Mobile has been encouraging their customers to use the app. She also told us T-Mobile is waiving any data charges associated with the app. Looking at the maps, it is clear that a large number of T-Mobile users are testing their phones all across the city.

We have provided links to the RootMetrics' map page. If you want to compare the results like we did, open up four tabbed browser windows, click on "network" and choose a mobile carrier for each window. To compare each of the different tests for the mobile carriers, click on "layer." Find the sector you are interested in, then zoom in to isolate areas of the Baltimore metro region.

If you would like to test the performance of your mobile carrier, download the RootMetrics' app, and run the tests yourself. The app is available for Android, iPhone, and Windows Phone. If you have a couple minutes to kill, here is a suggestion. Find a location not tested on the map. Use the app to run the test, wait a minute or two, then refresh the map to see your test results listed. In this way, you can help AT&T, Verizon Wireless and Sprint close the RootMetrics' testing gap in Baltimore.