A system and method for accurately matching corresponding DSP event data and Ad-Server event data with associated with a single real-world ad serve event by (a) pairing DSP event data and Ad-Server event data into data pairs, (b) comparing various field data in associated source fields from each of the DSP event data and Ad-Server event data to determine if the field data is a match or unmatch, and (c) based on the likelihood that a match of field data in a particular source field indicates an overall event match, which is determined using a Bayesian analysis, determining the probability that the DSP event data and Ad-Server event data in the data pair truly corresponding to the same single real-world ad serve event.