Despite best efforts, discrepancies in statistics are still quite a big issue for advertisers and publishers or between the advertiser’s statistics and the advertising platform's statistics. Typically, discrepancies of up to 10% can be acceptable; however, at times they can reach 20% and more. There are many different reasons why discrepancies occur. For example, counting methodologies can differ between parties, as each party can potentially count an impression at a slightly different point in the delivery of an ad (i.e. publishers can count impressions at the time the ad request is sent, while advertisers can count an impression when the creative/ad is delivered).
One thing to take into consideration is that before investigating any discrepancies always ask for most granular 3rd party report (e.g. hourly or at least daily). If discrepancies occur very suddenly, always check if anything was changed in campaign setup, (e.g. new creative added, new inventory sources added etc.).Read More