Abstract: The invention relates to medical billing systems, software, and methods. In the methods, a patient is told how much he or she owes to a hospital prior to or after discharge. The hospital then sells the right to collect the patient debt to a billing service. The billing service establishes an ad hoc credit rating for the hospital by analyzing an existing credit rating scale and fitting the hospital's financial data to that rating scale, and also establishes the patient's credit rating, expected recovery index (ERI) or other scoring metric. The hospital is advanced an amount that depends on the hospital's credit rating and the patient's credit scoring metric, and the billing service collects the debt from the patient, typically by regular automatic transactions. The billing service may interact with patients and hospitals through automated interfaces, and in some embodiments, may act as an affiliate of a health insurer.