Data Explained | How are you calculating video percent played metrics in Google Ads?

This metric is returned from Google Ads as a percentage. This dataset is using the "Ad Group" resource from the Google Ads API.  
Since we pull this value in as a percentage, the data is already aggregated (unlike something like impressions, which isn't). This means we can easily add things like impressions together in the dashboard, but things that come in already aggregated (like percentages) are a little trickier.

Let's look at an example. 

• On Monday, your video had 100 impressions. 
• On Tuesday your video had 150 impressions. 
• On Wednesday your video had 125 impressions. 

The API returns this data in this format, and in the dashboard, we can easily say for this three day period you had 375 impressions. 

For video percentage views, the data looks like this:

• On Monday, 25% of those 100 impressions watched half of your video. 
• On Tuesday, 30% of those impressions watched half of your video. 
• On Wednesday, 28% of those impressions watched half of our video. 

For impressions, the API is just keeping count. However, for the video percentage, it's actually calculating something, so adding them doesn't work (93% isn't right), and averaging them isn't great either since impressions were different each day (25% of 100 impression does not equal 25% of 150 impressions). 

TL;DR

For that reason, we use weighted average calculation OR you could derive the number of times the video was viewed to a particular percentage.

Here are examples of those calcs:

 SUM(video_played_to_50_percent * impressions) = # people who watched  50% of the video

(.25 * 100 + .30 *150 + .28*125) =  105
 
SUM(video_played_to_100_percent * impressions) / SUM(impressions) = Weighted Percentage 

(.25 * 100 + .30 *150 + .28*125) / 375 = 28%