1. A method comprising: obtaining a record of actual rental payments associated with residents of a portfolio of rental units corresponding to a rental unit; obtaining a credit rating for the residents of the portfolio of rental units; classifying the residents of the portfolio of rental units into at least one category based on the record of actual rental payments; and determining, by statistical analysis, a predictive indicator of a credit rating to associate with the at least one category based on the credit rating and the classification of the residents.