T-Mobile's claims that it has the nation's fastest LTE networks have been criticized by the National Advertising Division in the wake of Verizon calling the data behind them into question, and T-Mobile has in turn agreed to cease claiming that it has the fastest LTE network in the US based on the data in question. The data is Ookla and Open Signal speed tests conducted by users of both networks, which Verizon claims have been affected by recent network changes in a way that could unfairly favor T-Mobile. The carrier agreed to cease claims using that data, but is still claiming to have the fastest LTE network based on more recent data, which is theoretically unaffected by Verizon's claim.
Verizon is claiming that because it rolled out unlimited networks with deprioritization only recently, users who may not know what to expect and are using apps from Open Signal and Ookla to try to figure out what their network speeds are and why could represent a disproportionately large swath of Verizon users on the two apps for the period just after the unveiling. The National Advertising Division may have stood with Verizon in regards to that particular subset of data, but T-Mobile's insistence that it can continue to claim having the fastest LTE network at present because of newer test data has yet to draw comment from either Verizon, the National Advertising Department, or any other carriers.
It is worth noting that T-Mobile came in last place among the four US carriers in a recent RootMetrics network testing round. The round represented data that was a few months old as of the end of last year, and was meant to show data for each of the carriers that consumers could use to make an informed decision in regards to carrier shopping around that time. Those tests are conducted by having employees drive around the country with devices on each network, and measure them in various categories from area to area. This means that, unlike with something like an Ookla Speedtest that may only be conducted by users who are more concerned with network speeds, areas with demographics that are not terribly technically inclined or have a low population are represented just as strongly as any other parts of the country. T-Mobile has long struggled with rural coverage, and plans to correct this with its rollout of 600MHz long-range LTE, as well as its ongoing 5G rollout, which is currently in its infancy. It is also worth noting that T-Mobile CEO John Legere has made his disdain for RootMetrics' testing methods well-known in the past.
T-Mobile's SVP of Corporate Communications, Janice V. Kapner, has issued a statement regarding the NAD request for modifying its Fastest Network claim and Verizon's issues with the initial data that was used, stating that it "Looks like Verizon’s “cherry picking” what was actually covered in the NAD decision. Let’s break it down: NAD ruled on one claim that we don’t even use anymore. Next. Verizon tried to refute our claim that we cover 99.7% as many people as they do. We substantiated it and NAD agreed. Win for T-Mobile. On the fastest LTE network challenge, NAD ruled that the one month of crowd-sourced data we submitted (when Verizon launched their unlimited plan) could not be used. NAD previously recognized third-party crowd-sourced data as a way to look at network performance, so we looked at the latest results, and verified what we already knew! T-Mobile is still the fastest LTE network and we’ll continue to let consumers know that! Another win for T-Mobile and our customers!"