How do you explain a learning period to someone who wants results this week?

Two separate answers, because your two questions have different shapes. On framing. Don't explain learning as a waiting period. Explain it as a cost you already agreed to pay. The bidding is rebuilding its model of who converts, and while it does that it deliberately buys some traffic it is unsure about, because that's the only way to find out. You're paying for information. That is an investment with a term, and directors understand those - what they do not accept is being asked to be patient without being told what patience buys. On when it stops being true. Learning is about accumulating conversions, not days. The rough guide is a couple of weeks or around 30 conversions at the new setting, whichever comes later - and "whichever comes later" is the part everyone drops. On a campaign with five conversions a week, nine days is barely a third of the way there and reverting now means you paid the entire cost of learning and collected none of the benefit. So the answer to your director is a number: here is how many conversions we have accumulated since the change, here is how many we need before the result means anything, here is the date we hit it. If we are past that and still down, revert. Give him a date and a threshold and the conversation stops being about faith.