System and method to produce an anonymized cohort, members of the cohort having less than a predetermined risk of re-identification. The system includes a user-facing communication interface to receive an anonymized cohort request comprising traits to include in members of the cohort; a data source-facing communication channel to query a data source, to find anonymized records that possess at least some of the requested traits; and a processor programmed to carry out the instructions of: forming a dataset from at least some of the anonymized records; calculating a risk of re-identification of the anonymized records in the dataset based upon the data query; perturbing anonymized records in the dataset that exceed a predetermined risk of re-identification, until the risk of re-identification is not greater than the pre-determined threshold, to produce the anonymized cohort; and providing, via a user-facing communication channel, the anonymized cohort.