I just ran a split test FB ad and got 45 clicks on Books2Read but FB recorded 76 clicks. FB emailed me and said the winning ad got 45 clicks. So I am wondering where the clicks on the loser ad went and why Books2 Read apparently doesn't have them. I don't know if there's a lag in reporting. I used up a $30 credit FB had sent me, so the test cost nothing. Apparently, the ad produced 4 sales over the baseline for that title.
The credit makes up a little bit for the FB ads I ran over a month ago that cost $85 and produced only 1 sale. Those show only 7 Books2Read clicks, yet FB said the two ads had a combined total of 132 clicks. The ad copy and the cover art made it very clear what the book was about, so I guess there was more curiosity than actual interest. But maybe subject matter fans thought it was nonfiction at first. Although why a box set should be presumed to be fiction baffles me.
I finally added a FB pixel to my Books2Read, and confirmed with them that it was correct. But I have no idea where to find any data from it.