Once you've double checked that the number of impressions you're expecting to see recorded in Revive Adserver is correct, then move on to the next step.
3: Check for Impressions Against Expired Campaigns
Revive Adserver needs to keep the details of your past campaigns and banners in the database, to allow you to view the details of past delivery statistics.
However, this means that it is possible that due to caches, agents (such as spiders) may continue to access the impression logging URL of banners, even after the campaigns the banners are in have ended, and Revive Adserver will continue to record the impressions against these banners.
Revive Adserver does offer a feature to prevent impressions being recorded against expired campaigns - consider enabling this feature, if not already enabled.
Step 3: Consider Location of the Analytics Tag
Review the location of the page analytics tag, if that's how your page views are recorded.