Remember back in late May when we told you about the Internet Health Test? The simple test analyzed users’ Internet connections from end to end, and it aimed to determine whether or not Internet service providers might be violating the Federal Communication Commission’s new net neutrality rules by intentionally slowing data connections.

This week, the group behind the Internet Health Test has released the results of a study that analyzed tests performed by more than 300,000 Internet users, and it appears as though the test has served its purpose: Five major ISPs in the United States have been accused of deliberately slowing data from popular websites in dozens of cities across the country.

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The Internet Health Test website launched last month is the brainchild of BattlefortheNet.com, a consortium of activist groups that are dedicated to an open and free Internet. The site encourages Internet users to perform a simple test that takes less than one minute, and it analyzes data connections in an effort to determine whether or not ISPs are intentionally slowing data speeds.

According to early findings released in a report this week, the answer is yes, ISPs are indeed slowing connections in many cases.

Time Warner Cable, Verizon and AT&T are among five ISPs named in the report that have been accused of deliberately slowing data traffic from certain Content Delivery Networks (CDNs). Popular web services with heavy traffic pay CDNs to help store and serve their content.

As an example, the study found that Comcast provided median download speeds from one CDN of 21.4Mbps during peak evening hours. During the same time period, AT&T provided median download speeds of 0.2Mbps.

“For too long, internet access providers and their lobbyists have characterized net neutrality protections as a solution in search of a problem,” Tim Karr of Free Press, which is one of the groups behind BattlefortheNet.com, told The Guardian. “Data compiled using the Internet Health Test show us otherwise – that there is widespread and systemic abuse across the network. The irony is that this trove of evidence is becoming public just as many in Congress are trying to strip away the open internet protections that would prevent such bad behavior.”

The group encourages Internet users to continue to utilize the Internet Health Test website, which can be found by following this link.