Geographic dimensions of broadband data uncertainty

This article reviews sources of uncertainty in broadband provision data from Federal Communications Commission’s Form 477 database, which is the largest publicly available broadband database for the United States. This uncertainty analysis reveals that reporting thresholds result in understating of broadband in rural areas serviced by smaller providers in the 1999–2004 ZIP code area dataset. In this same time series, the routine used to aggregate data to larger spatial units (i.e., counties) produces variations in the amount of autocorrelation detected by diagnostic spatial statistics. The amount of autocorrelation in the data also varies with the strategy implemented for interpolating suppressed data. This investigation also highlights the value of a spatial approach to visualizing and analyzing the impact of uncertainty on broadband availability.