A system and method for assessing demographic data accuracy from third party data vendors is provided. Third party demographic data is compared to self-reported demographic data; hence compared to data presumed to be accurate. Analysis is done on the comparison to determine the accuracy of the data and if bias exists in the results for a particular demographic population or geographic region. Demographic data from many third parties can be analyzed in the same way, and the results can be compared to each other to determine which third party has the most accurate demographic data elements.