The number of times a user sees an ad over a set period of time.
It’s calculated by dividing total ad impressions by total ad reach. Frequency over 1.00 means at least some users saw your ad multiple times. This may be positive if your goal is to raise brand awareness and ad recall, but if your frequency is very high you may be wasting your budget and advertising too many times to each user.
In another word, average frequency is the average
number of times each user is shown
an ad during the campaign's duration. user sometimes typically require multiple exposure opportunities to an advertiser’s content before they convert.