The building violation complaints data is taken from 311 open data; The certificate of occupancy issuance data is taken from DOB open data. All data in this research rely on data from year 2016 and were cleaned to focus only in residential information. Any personal information was excluded from the datasets pre-importThe 311 complaints data were filtered to include Building/Use complaint type only, and then filtered again by descriptor to include illegal conversion of non residential buildings/units to residential without obtaining approval from the New York City Department of Buildings (excluding illegal vehicle storage, for example).