The use of data to support the holding accountable of predatory landlords is, so far, limited. Many of the existing uses are not publicly available, and many are not done in a way that is scalable beyond a specific building or portfolio. There have been some larger scale, public and data-driven efforts to quantify the quality of housing for New York City residents, but these efforts are not geared towards holding specific landlords to account. (Rentlogic)(Displacement Alert Pr...)Our team is looking to fill this gap between legal advocacy and data-driven work. Based on a model of predatory landlord behavior, we identify indicators in public and private data sources that point to the systematic and illegal harassment of tenants by New York City’s landlords. This comprehensive set of methods can help bring rigor and extensive coverage to the investigation of landlords. The case studies we present in this paper demonstrate this, while also showing the unique nature of each landlord’s portfolio and set of suspected predatory tactics. Ultimately, while it is not possible to use data to prove definitively that landlords are engaging in illegal behavior aimed at harassing tenants, the set of methods presented in this paper, when applied together, can paint a damning picture of a landlord by showing they are likely engaged in a plethora of predatory actions throughout the property ownership cycle.