The Discrepancy, sometimes also referred to as “Third-Party-Discrepancy”, is the difference between numbers reported by a publisher and a third-party ad server.
Publishers and advertisers in online and mobile advertising are usually running independent ad servers to manage their campaigns. Since each of the parties involved in the advertising process counts ad impressions at a slightly different point in the delivery of an advertisement (publishers count at the ad request, advertisers count when the ad is delivered), the reporting from either system never matches the other.
In general, discrepancies can occur due to different reasons:
- Different tracking methods
- Cache busting
- Time zone differences
- Connection problems
- Third-party tags
Although companies can take steps to minimize discrepancies to a certain extent, at the end of the day they will not be able to completely avoid them. Generally discrepancies between a publisher’s local ad server and a third-party ad server should never exceed 5-10%.