FB Ads Book · Chapter 5 of 7
Optimizations
Where Do Learnings Take Place?
- Learning takes place at ad level, NOT ad set level.
- Adset level learnings have some effect bunch are much less important
- Learning means predicting click-through rate and post-click conversion rate.
- Post-click conversion rate needs to be at the very least 0.5%, preferably over 1%.
- Each ad must have 25 lifetime conversions for delivery optimization to work.
- Each new ad needs to run for 36 hours until learning takes effect
What Will Reset Ad Learnings?
- Changing bid and budget is OK and will not reset learnings.
- Changing just about anything else (title, message, photo, …) will reset learnings because FB considers this to be a new ad.
- If the ad goes to review process that will definitely mean that learning for that ad starts from scratch.
Account level learnings
- Accounts also collect learnings (used as priors for new ads).
- It is not fair to compare performance against an existing account. All cross-account bake-offs MUST use new accounts.
- New accounts use country/objective level priors.
Delivery issues
- Most common cause of delivery issues:
- What to do if you do not get delivery:
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- Massively increase bid (or budget if the adset if budget limited).
- If using autobid increase budget.
- Relaunching the ad might also help because there is some randomness in getting initial conversions.
Deduping
- Deduplication happens also on object level (page/app).
- If another account shows ads for the same page, only one of the accounts will be able to show an ad for each user.
- This is why you absolutely must use an ad study with bake-offs
AutoBid
- Autobid will keep increasing your bid so that the budget is spent; in theory it should always spend the entire budget.
- Bid can go up to 95th percentile of bids in country/objective; there is no fixed dollar cap otherwise.
- The bid distribution is not updated in real time, so when bids suddenly increase (e.g. on Black Friday) the cap might be much lower than 95th percentile and hence auto-bid fails to spend the budget.
Fun Facts
- 25 conversions is enough to provide roughly 90% accuracy for predicting conversion rates.
- Facebook uses up to 90 days of user level data in optimization. This is based on EU regulations but the same 90 days is commonly used throughout Facebook.
- There is time decay for learning, so last days matter more. This also depends on the amount of data: if you spend over $10k per day and get tons of impressions then older data has less influence.