A computer implemented method of reconciling customer records between a plurality of sites, comprising: assigning a unique record number to a customer record; retrieving demographic information for a customer record in a system under consideration, to match said demographic information against demographic information in a collection of records in other systems to find records that belong to the same customer; comparing the customer record demographic information with at least one other record demographic information in the collection of records in at least one other system to derive a likelihood ratio for each compared record; comparing each likelihood ratio to a defined accept threshold and to a defined reject threshold, wherein the likelihood ratio comparison comprises one of: - rejecting the compared customer records if the likelihood ratio falls below a reject threshold ratio, - accepting the compared customer records if the likelihood ratio falls above an accept threshold ratio, and - identifying the customer records for a manual review if the likelihood ratio falls between the accept threshold and the reject threshold; the method further comprising: attaching an assertion for the compared customer records based on at least one likelihood ratio comparison; and placing the customer records to be manually reviewed on an exception list and distributing the exception list to the plurality of sites, and recording a determination of an accept or reject result made by manual review at each relevant site; wherein the step of determining the accept or reject result is performed at two or more of the plurality of sites, and wherein the method further comprises: notifying the two or more of the plurality of sites when two of the sites make conflicting assertions about a common record. assigning a unique record number to a customer record; retrieving demographic information for a customer record in a system under consideration, to match said demographic information against demographic information in a collection of records in other systems to find records that belong to the same customer; comparing the customer record demographic information with at least one other record demographic information in the collection of records in at least one other system to derive a likelihood ratio for each compared record; comparing each likelihood ratio to a defined accept threshold and to a defined reject threshold, wherein the likelihood ratio comparison comprises one of: - rejecting the compared customer records if the likelihood ratio falls below a reject threshold ratio, - accepting the compared customer records if the likelihood ratio falls above an accept threshold ratio, and - identifying the customer records for a manual review if the likelihood ratio falls between the accept threshold and the reject threshold; the method further comprising: - rejecting the compared customer records if the likelihood ratio falls below a reject threshold ratio, - accepting the compared customer records if the likelihood ratio falls above an accept threshold ratio, and - identifying the customer records for a manual review if the likelihood ratio falls between the accept threshold and the reject threshold; the method further comprising: attaching an assertion for the compared customer records based on at least one likelihood ratio comparison; and placing the customer records to be manually reviewed on an exception list and distributing the exception list to the plurality of sites, and recording a determination of an accept or reject result made by manual review at each relevant site; wherein the step of determining the accept or reject result is performed at two or more of the plurality of sites, and wherein the method further comprises: notifying the two or more of the plurality of sites when two of the sites make conflicting assertions about a common record.