I just conducted a split test and got the exact opposite results as expected. My goal was to compare the cost of having a custom audience (scraped) and compare it to an identical audience through Facebook's standard targeting (FBX). I expected it to be cheaper since Fb would think that they were truly my audience. FBX cost per conversion: $1.51 WCA cost per conversion: $4.41 FBX reach: 20k WCA reach: 8k Any idea on why the hell this is happening? The ads are identical (zero variations), the only thing I didn't do that might have affected it was exclude my WCA list from the 2nd set of ads so maybe they were directly competing against each other? I thought WCA was supposed to be cheaper. What am I missing? I tried attaching pictures from imgur of the report but it isn't letting me.