I have the same metric to analyze from Google Ads on two different periods (last 7 days vs last period). I would like to the see the variation between these two periods in a separate scorecard like in the screenshot
I assume you can use filters and scorecards to get the two scorecards, right?
And so your question is about how to get the green 7.3% comparison metric to show up?
The key there is to have both data points in the same data table. You’d want a table where the first row is 40.75% and the second row is 37.99%. Then Looker Studio could compute and show the comparison. If your periods are uniform - like this week vs last week - then you can use the week dimension to get this grouping easily.