This case study presents the research process to assess the effectiveness of a nuisance rental property ordinance. The effectiveness of the ordinance was largely determined by examining pre- and post-ordinance data in the form of reported crime with an interrupted time series design. Five years of pre-ordinance data were examined against 5 years of post-ordinance data (1999-2009). The internal validity of the results was strengthened using a non-equivalent dependent variable, which was crime outside of rentals and not intended to be impacted by the ordinance. The ordinance and subsequent expectations of rental property managers are supported by the concept of third party policing. The research findings showed that the ordinance was highly effective in reducing crime and disorder in nuisance rental properties.