We had a good quarter and everyone is happy, but when they ask me which of my campaigns did it, I honestly cannot say. I ran five things at once and the sales went up, and I have no real way to know which one mattered. I nod along in the meeting, quietly afraid someone will realize I am guessing.
More people experience this than they realize.
You can't tell which of your efforts actually drove the result.
If this sounds familiar, the Library can help you find the bigger picture.