How is Banner Ads Impressions counted

[Sloke]

Hi,
I am trying to make an app that explains ads functionality for my Uni Assignment.
I have disabled the banner ad's auto refresh, I want to refresh it manually by making a 2nd network call.

However, I am unclear on how a banner ad impression is counted. The OnImpression event is fired as soon as the ad is loaded. But that doesn't sound right. Why would a developer choose a lower refresh rate over high?

Thanks

[Mobile Ads SDK Forum Advisor]

Hi Sloke,

Thank you for reaching out to us.

With regard to your concern, an impression is counted when one or more pixels of the ad creative is visible on a device's screen. We always recommend our publishers to use the Google optimized automatic refresh rate. The optimized rate is calculated using AdMob historical data to ensure the ads shown in your ad units are being refreshed at the best rate for banner ads.
 

This message is in relation to case "ref:_00D1U1174p._5004Q2nrxSX:ref"

Thanks,
 

Mobile Ads SDK Team