Cellular Mapping Limitations

For the moment, Broadband Map primarily relies on measures of signal strength. While signal strength generally serves as a good proxy for connection quality, it doesn't account for everything that can affect users' experiences. For example, congestion levels often have a dramatic effect on the speeds experienced by network users. Congestion can be severe despite strong cell signals. At the moment, Broadband Map does not account for congestion levels in its maps.

FCC Data

Broadband Map relies primarily on data that network operators report to the FCC through the Broadband Data Collection program. Network operators estimate coverage areas and coverage strength using statistical and geospatial models. While the estimates are informative, they're imperfect.

Some parts of the FCC's coverage-modeling process are standardized, but network operators don't take entirely identical approaches. Further, the FCC uses data it collects to inform decisions about telecom policy and subsidies. In some scenarios, network operators may be incentivized to understate or overstate coverage.

Crowdsourced Data

Broadband Map collects crowdsourced data assessing the on-the-ground performance of networks. The crowdsourced data allows Broadband Map to adjust and account for many of the limitations in the FCC's data. However, there are also limitations in the crowdsourced data as well.

Much of Broadband Map's crowdsourced data comes from data collected on a device designed to collect data about vehicles. The device's hardware and the manner its used in won't perfectly match the phone hardware and behavior of typical consumers.

Crowdsourced data coming from consumer handsets mixes a variety of contexts: indoor, outdoor, stationary, and in-motion. The mix of contexts represents how real consumers use their phones, but it complicates using and interpreting the data.