Movement between unserved -> underserved -> served over the last three Form 477 filings

My previous post showed the “current” state of un- and underserved by broadband, according to the FCC’s Form 477 from December 2020. It showed that in the short time since RDOF grants were awarded there has already been drift away from purely unserved areas. There are 1 million housing units that have been authorized for RDOF grants that are currently underserved (between 25/3 and 100/20), and 352,000 housing units that are served by broadband. Conversely, I will admit to thinking of RDOF Phase I as including all the unserved at the time. But that isn’t the case. There were exclusions, most importantly for non-high cost areas. As a result, of the 3.78 million unserved housing units, 1.98 million were not even RDOF-eligible.

This got me thinking: how quickly has broadband deployment progressed. How fast have Census blocks moved from unserved to underserved, or served. And is there any movement in the other direction? From served areas to underserved or unserved?

To visualize these questions I used a Sankey diagram, which shows movement across time. For the whole United States, there were 6.76 million unserved housing units in the Dec 2019 Form 477 data. 950,000 of those housing units moved to underserved in the next update for June 2020. 402,000 became served. By the Dec 2020 update, we’re at 3.78 million unserved housing units, which includes a small amount of movement towards unserved, but mostly movement away, as expected.

At the bottom of this link is the Sankey diagram for each state.