Abstract: A prescription association system and method for grouping together prescription-related transactions and creating groups or “clusters” of prescriptions having similar characteristics. Through an association process, the prescription cluster describes the events surrounding prescription activity. This includes prescribing patterns, payer influences, and patient acceptance of therapy. The same prescription transaction from one data provider may contain additional or different information that can enhance a corresponding duplicate transaction or set of claim lifecycle transactions from another provider. The disclosed processes create unique linking across claims, payers, and patients and form the basis for relating and measuring payer, patient, practitioner, and pharmaceutical promotion influences on healthcare utilization and treatment.