Broadband Data Improvement Act of 2019 This bill requires (1) broadband service providers to fulfill certain reporting requirements, and (2) the Federal Communications Commission (FCC) to establish a challenge process to aid in broadband mapping. Specifically, the bill requires each provider to report certain information regarding the geographic availability of broadband service it provides. The FCC must contract with an entity to provide data submission assistance to a provider that is unable to comply with this reporting requirement. Among other responsibilities, such entity shall provide support for the required challenge process and establish an ongoing data validation and verification process. The FCC is also required to establish a framework for a process whereby information challenging the accuracy of the National Broadband Map may be submitted. Subject to the challenge process and feedback received therefrom, specified federal agencies shall use the National Broadband Map to determine the extent of broadband availability and the areas of the United States that remain unserved.