There have been a lot of grumblings about inaccuracies in the National Broadband Map released earlier this year, including some from Telecompetitor readers. This week, ID Insight, an organization that independently tracks broadband availability, issued a formal critique of the map that attempts to quantify the map’s inaccuracies.

ID Insight maintains a database about nationwide broadband availability, which it calls BroadBand Scout. In a report titled “Verification Analysis of the National Broadband Map: Spotlight on Arizona,” issued this week, ID Insight explains that its database “was created by looking at over a half a billion consumer Internet transactions that link the consumer’s physical address to their Internet provider through their Internet protocol (IP) address.” Those transactions, the company said, cover approximately 15% of all Internet households in the country.

In contrast, the National Telecommunications and Information Administration, which created the National Broadband Map, collected its data from carriers, some of whom apparently did not respond to NTIA requests or were not queried. Of those carriers that did respond, some apparently overstated broadband availability. Accordingly, the NTIA data underestimates broadband availability in certain geographic areas and overstates it in others, the ID Insight report says.

ID Insight did a detailed analysis of the state of Arizona, comparing its data with the National Broadband Map and found that 95% of the time, the Arizona map and BroadBand Scout data agree with respect to broadband coverage. The company notes, however that “when we isolate the more rural counties, only 85% of the time do they agree.”

Researchers also noted that only 74% of targeted providers in Arizona contributed data. Of the targeted providers, ID Insight scout said it observed 96%.

“The initial version of the National Broadband Map . . . is a great first step of where our country is with respect to broadband infrastructure,” said Adam Elliot, president of ID Insight, in an announcement of the research findings. “At the same time we all understand that it is a work-in-progress and we need to continue to improve our understanding of where broadband is and is not.”

Elliot suggested that it would be wise for the NTIA to use an independent database such as BroadBand Scout to verify its findings as part of the map update process.