What Speed Tests Might, and Might Not, Indicate

What does this plot of speed tests conducted by U.K. consumers tell us? In principle, it only tells us that there are fewer tests on copper connections; about the same number of tests on hybrid fiber coax networks; declining tests on fiber-to-curb networks; while fiber-to-home customers conduct more tests.

Presumably, the number of tests is related to the number of accounts. But the number of tests also could be related to the number of trouble tickets or network issues. Most of us are prompted to test only when there is some obvious connectivity issue. 

But it also is possible that users on some of the latest networks (FTTH) are testing for other reasons, such as verifying that speeds are really faster than on the older networks. 

source: Think Broadband 

Also, since most such tests appear to be conducted from Wi-Fi-connected devices, the number of tests also likely reflects Wi-Fi issues that users are having, and that is more a reflection of indoor Wi-Fi issues than a reflection of the access network connection. 

Actual internet service provider delivered speed is going to be higher than what a Wi-Fi test shows, and also could be lower if multiple other apps or multiple users are active during the test period.

Testing algorithms also vary, which is why the same device, on the same network, yields different test results when different testing services are used. All this data appears to be from the ThinkBroadband test, so results should be comparable.

The point is that historical data on "speed" is shaped by the testing methodology: users mostly test on Wi-Fi, which almost always is slower than the ISP's "to the home" speed.