MassGIS officials emphasize statewide Master Address Database as a foundation for 2030 Census work

Massachusetts' statewide address effort is centered on the Massachusetts Master Address Database (MAD), MassGIS officials told the Senate Committee on the Census on Sept. 22, and the MAD will again be a core input to the state's preparations for the 2030 Census. "The primary reason for the creation of the MAD was a public safety need," Dan Marrier, senior GIS specialist and database architect at MassGIS, said. He described how MAD address points are geocoded to building footprints to improve accuracy for emergency response, and how multiple administrative sources are normalized into a single master record. MassGIS said the MAD combines many different inputs — E‑911 records, assessor parcel data, voter registration records, motor vehicle registrations, property sales and utility information — and that cross‑referencing those sources improves accuracy. MassGIS records show roughly 2.9 million addresses identified as residential in its master table, more than 2.2 million address points and over 2.5 million building footprints in its inventory. MassGIS maintains a monthly editing workflow and receives direct municipal updates via a dedicated notify e‑mail and through annual assessor/parcel submissions tied to public safety grant eligibility. Why it matters: the MAD was used directly in the Census Bureau's Geographic Support Services Initiative prior to 2020; MassGIS said that transfer led the bureau to update more than 1,000,000 address and point locations. Dan Marrier said the MAD remains critical for LUCA, Count Review, group‑quarters inventories, and the state's population estimates and planning work. Technical issues and municipal roles: MassGIS staff said municipalities remain the authoritative local addressing authority and that local participation is essential. MassGIS also described efforts to standardize assessor use codes (reducing roughly 5,000 unique assessor use code/descriptions into about 100 standardized codes) so the state can filter for residential addresses and identify likely conversions and accessory dwelling units (ADUs). The bureau noted Boston maintains its own addressing data and coordinates updates with MassGIS. Ending: MassGIS staff asked for continued municipal cooperation and described internal capacity (12 full‑time staff) and services to support local governments and the Secretary of the Commonwealth's office in the LUCA and BBSP windows.