1. An apparatus for estimating a propensity to pay an owed amount to a revenue agency, comprising: a memory; and a processor configured to retrieve instructions from the memory and to perform; for each of a plurality of score bands of a collections model, wherein each score band corresponds to a different credit score rang; assigning to the score band a different scoring expression specially determined for the score band; obtaining a first credit score for a first debtor; selecting, based on the first credit score, a first score band from the plurality of score bands; and in response to the selecting, applying the scoring expression assigned to the first score band to first raw credit data and first tax form data to determine a first collection score for the first debtor.