The primary source of the permit data was the residential permit dataset that the City of Portland shared with the public through its Open Data Portal. This residential permit dataset contained all residential permits that had passed the city's preliminary reviews from the mid-1990s to June 30, 2023, the most recent date at the time of analysis. This dataset offered comprehensive information concerning each new construction permit, including permit application number and date, issue date, permit status, address, building type, number of dwelling units, building floor area, and brief permit work description. Notably, this data set did not include the most recent residential permits that were submitted but had not passed preliminary reviews.