1. A method for measuring healthcare quality, the method comprising the steps of: a plurality of computers receiving a patient dataset in a plurality of different formats representative of patients within a healthcare organization, wherein the plurality of computers form a computer cluster and operate in parallel; the plurality of computers converting the patient dataset from the plurality of different formats to a common format and indexing the patient dataset to be searchable; the plurality of computers distributing the patient dataset across the plurality of computers as subsets of patient datasets; the plurality of computers receiving at least one healthcare quality measure definition comprising a numerator and a denominator each representing a quantity of patients; each of the plurality of computers independently identifying, in the subsets of patient datasets, patient data that corresponds to the measure definition; each of the plurality of computers independently attributing the identified patient data to at least one provider based on an attribution rule; each of the plurality of computers independently calculating a quantity of distinct patients for the numerator and denominator for at least one healthcare quality measure for the at least one provider, according to the healthcare quality measure definition, to determine the at least one healthcare quality measure based on the attributed patient data, wherein a plurality of a same patient within the attributed patient data is consolidated by the plurality of computers to a single patient for determining the quantity of patients for the numerator and denominator based on occurrence of a plurality of encounters for a same medical condition between a provider and the same patient within a time period; and the plurality of computers combining results from the plurality of computers to calculate the at least one healthcare quality measure and storing the at least one calculated healthcare quality measure in a measure dataset.