Good day, hope you all doing great. Few days back I received a notification under Optimization tab in Google Adsense that one of my link ad unit needs an optimization in order to improve its performance. I mostly avoid that kind of recommendation because by experience I'm aware of my audience and niches that what kind ads perform best. But this time I decided to give it a try because I noticed there is an option of "Run Experiment" right next to the notification.
So Finally, I decided to run an experiment based on their optimization tip; which says your link unit border has to be have the same color as of its background color for better performance. I found it so simple to create. You just have to click on Run Experiment and then Google Adsense will initiate it itself.
The experiment ran for 3 days, and during all that time, I thought may be the border color isn't making any difference thats why its taking so long. But I was wrong, after gathering 36 thousand ad impressions, Google Adsesne jury made an announcement with 100% confidence that I was right. My original link unit ad was chosen as winner over there recommended ad unit with variation in border color. YEAHHH!!!! :D
As you can see in above screenshot, because of the changes they recommended the RPM decreased by 22%, Quality Score over 40%, and the overall performance decreased by 61%. And thats huge.
So, the conclusion of this interesting story is to be confident on what you are doing. Especially, don't get confuse and apply experiments when your site is getting tons of traffic for a very limited duration like for few hours or 4-5 days as we observe during events or when posts goes viral on social media, etc. Mine website was kind of small semi seasonal, so it didn't make much difference, but, if you will do the math, it still costed me $4.872 USD because of drop in RPM. Over to you!