The harassment of tenants, particularly socially vulnerable tenants in rent stabilized units, is a critical issue in New York City. A significant amount of work is being done by regulatory agencies, non-profit organizations and community activists to combat predatory landlords and protect tenants, but much of this work is being done on a building by building or portfolio by portfolio basis. Given the scope and magnitude of this problem, an approach for identifying and characterizing predatory landlords that can scale to portfolios across New York City is needed. The methodology, analysis and tool our team have presented in this paper form the foundation for such an approach. The technical and institutional challenges necessary to implement such an approach at scale are substantial. On the technical side, a more robust data validation would be needed to ensure the representativeness of the self-reported data. Further testing based on a larger and more detailed training set of known bad landlords should be incorporated to validate and refine the indicators proposed here. And to truly scale this approach, our tool must be automated and all portfolios in New York City must be queried to facilitate real-time and city-wide use. On the organizational side, there is the major challenge of incorporating of a city-wide, portfolio scale tool for the flagging of landlords suspected of rental intimidation into the city's existing regulatory processes, many of which at the building level and many of which already facing substantial backlogs. And given the highly politicized nature of the real estate sector in New York City it may be hard to find the willingness to invest in a tool targeting landlords, even if they are landlords who harass their tenants. However, the resolution of these issues and the implementation of such a tool would result in a substantial improvement in the way regulators and community activists go about identifying, characterizing and ultimately holding accountable New York City's predatory landlords.