1. A system for detecting fraud, the system comprising: a self-calibrating outlier model hosted by a computing system, the self-calibrating outlier model receiving transaction data representing transactions, and being configured to calculate transaction-based variables, profiles and calibration parameters, and to produce a score based on the transaction data according to the transaction-based variables, profiles and calibration parameters; and an adaptive cascade model hosted by the computing system, the adaptive cascade model being configured to generate a secondary score for the transaction data based on profile information from the variables and/or profiles calculated by the self-calibrating outlier model, and based on a comparison with labeled transactions from a human analyst of historical transaction data.