Key takeaways
- Run the after action report within 48 hours, on six questions, while everyone still remembers what happened.
- Do not treat those numbers as final. Around 17% of holiday sales come back as returns, and in one account we manage roughly 31% of conversions landed more than seven days after the click.
- Judge the sale on MER and contribution margin, with new customer CAC next to them. Platform-reported ROAS double counts hardest during exactly the week you most want to trust it.
Most brands spend four months planning Cyber Week and about forty minutes reviewing it. The sale ends, someone pulls a revenue number into a Slack message, everyone says nice work, and the account rolls into December.
That is an expensive habit. The week after the sale is the only time all year you have a clean, high-volume, high-intent dataset about your own business, and it is the only input you will have when you plan the same event next July. If you do not capture it while it is fresh, you will rebuild next year’s plan from memory and last year’s spreadsheet.
Here is the review process we run, what to look at immediately, and the part almost everyone gets wrong: knowing which numbers are already final and which ones are not.
Run the After Action Report Within 48 Hours
The after action report, or AAR, is not the analysis. It is the fast read you send while the sale is still fresh, usually the Tuesday morning after Cyber Monday. Upper management is going to ask for a number that day whether you have prepared one or not, so it pays to have the answers ready.
Six questions, and it should take under an hour:
- Did we hit our revenue goal?
- Did we hit our inventory goals?
- Did any product go out of stock that our projections did not anticipate?
- How much did we spend during the sale?
- What was our total MER (marketing efficiency ratio) for the sale?
- What did we pay to acquire a new customer, and how does that compare to a normal week?
Answer those, send it to the teams that need it, and stop. The AAR exists to close the loop quickly and to capture the things people forget within a week: which creative the team scrambled to swap, which landing page broke, which platform took two days to approve an ad. Those details never appear in a dashboard and they are the ones that change next year’s timeline.
Then Stop. Your Numbers Are Not Final
This is where most post-sale reviews go wrong. The AAR gets treated as the verdict, budget decisions get made on it, and then the real numbers arrive weeks later and nobody revisits the conclusion.
Two things are still moving.
Conversion lag
Conversions keep landing after the click, and considered purchases land late. In one account we manage, roughly 31% of conversions arrived more than seven days after the click. Pull a report the Tuesday after Cyber Monday and you are looking at a partial view of a window that has not closed.
This matters most for the channels you are most likely to cut. Upper-funnel and prospecting campaigns carry the longest lag, so an early read makes them look weakest at exactly the moment you are deciding what to keep funding in December.
Returns
The National Retail Federation puts holiday returns at about 17% of holiday sales, against roughly 19% for online sales generally, and industry estimates run to 20-25% of holiday merchandise once gifting and impulse buying are counted. January is the peak returns month, and peak-season return volume can run three to five times a normal day.
A sale that looked like a record on Tuesday can look materially different in February. If your reporting counts gross revenue and your business runs on net, you are reviewing a number the business will never actually see.
What that means for the report you just sent
Nothing, as long as you said so in it. Put a line in the AAR stating that the figures are preliminary, that conversion lag and returns are still outstanding, and that a revised read follows. That one sentence prevents a quarter of bad decisions, because it stops a provisional number from hardening into a fact.
The Full Performance Review, One to Two Weeks Out
This is the one that changes next year. Give it a week to ten days so the lag has mostly resolved, then go through the account properly.
Channel and campaign
Break performance down by channel, campaign, ad set and audience. You are looking for the specific things that beat or missed your own benchmarks, not a ranking. When something underperformed, rule out the boring explanations first: did it actually deliver, did it exit the learning phase, did it lose budget to a neighbor in the same campaign. Plenty of campaigns that look like creative failures are delivery failures.
Creative
Which ads carried the sale, and were they the ones you expected? Cyber Week compresses the normal testing cycle, so a creative that won during the sale won under unusual conditions: higher frequency, a hotter auction, and an audience already primed by whatever you ran in September and October. That does not mean it wins in February. Note which ones held up and which ones only worked with a discount behind them.
The site and the funnel
Walk the entire customer journey, not just the ads. Where did sessions drop out? Did the checkout hold up under load? Did the promo apply cleanly everywhere it was supposed to? The traffic volume during Cyber Week makes site problems visible that a normal week hides, which makes this the best diagnostic window you will get all year.
Judge the Sale on MER, Not Platform ROAS
Platform-reported ROAS is at its least reliable during a promotion. Every channel is running hard at the same audience in the same week, so the same purchase gets claimed in multiple places and the sum of your platform numbers can comfortably exceed the revenue your business actually recorded.
Use MER, total revenue divided by total marketing spend, as the headline. It is blended, so it cannot be double counted, and it maps to what the business actually experienced. Then layer contribution margin on top, because a sale run at 30% off with elevated returns and higher shipping costs is a very different outcome than the revenue line suggests.
MER will not tell you what the sale cost you in customers. Run new customer CAC alongside it, total marketing spend divided by first-time buyers, and hold it against a normal week.
The complication is who the discount actually pulled in. Some of those buyers are new to the brand. Others were going to buy anyway and waited for the sale, which is a rational thing for a customer to do and exactly what a predictable discount calendar teaches them. Both groups land in the same CAC number, and the second one makes it look cheaper than it was, because you paid media costs to acquire someone you already had and gave up margin on the order as well.
Acquisition is not the point of the sale, but it is one of the outcomes, so it belongs in the review. Split first-time from returning buyers before you calculate it, and label the figure preliminary like everything else, because returns take buyers back out of the count.
If you want to know what your ads actually caused rather than what they touched, that is a separate question, and the answer is a holdout rather than a report. Our guide to incrementality testing covers how to structure one. Cyber Week is a poor time to run the test itself, but the period right after it is a good time to plan the next one.
The Cohort Question Most Brands Skip
Cyber Week is usually the largest single intake of new customers a brand gets all year, and almost nobody goes back to look at what happened to them.
The benchmark to hold it against: DTC repeat purchase rate sits around 18.8%, meaning roughly four in five customers buy once and never return. Of the ones who do come back, about half do it within 30 days and roughly three quarters within 90. So the window in which you find out whether your Cyber Week cohort was worth acquiring is short, and it opens immediately.
Tag the cohort, then check repeat purchase rate at 30, 60 and 90 days against your normal cohorts. Deep discounts attract deal seekers, and a cohort acquired at 40% off that never buys again at full price is a customer acquisition cost you have not really paid for yet. This is where your post-purchase flows earn their keep, and where a strong Cyber Week either compounds or quietly does not.
Write It Down Before You Forget It
The output of all this should be one document you can hand to whoever plans next year, including yourself. What the goals were, what actually happened, what you would change, and what you would not.
Be specific about the operational things, because they are the ones that get lost. Which platform took three days to approve creative. Which asset arrived late. Which inventory assumption was wrong. When you sit down in July to build next year’s Q4 plan, that document is worth more than any dashboard, because it is the only record of why the numbers looked the way they did.
The brands that improve at this every year are not the ones with better tools. They are the ones that wrote down what happened while they still remembered it.
Frequently Asked Questions
How soon after Black Friday should I review performance?
Run a short after action report within 48 hours, covering revenue, inventory, spend, MER and new customer CAC, and label the numbers preliminary. Run the full performance review one to two weeks later, once conversion lag has mostly resolved. The fast read is for communication. The later one is for decisions.
Why do my Black Friday numbers keep changing after the sale ends?
Two reasons. Conversions continue to land after the click, and considered purchases can land more than a week later. Returns then reduce the revenue that stuck, and holiday returns run around 17% of holiday sales with January as the peak month. Gross revenue on the Tuesday after Cyber Monday is a provisional figure, not a final one.
Should I use ROAS or MER to judge a Cyber Week promotion?
MER. During a promotion every channel is targeting overlapping audiences in the same short window, so platform-reported ROAS double counts more than usual and the platform totals can exceed real revenue. MER is blended and maps to what the business actually recorded. Layer contribution margin on top so the discount and the returns are visible, and track new customer CAC next to it, because the sale acquires customers whether or not that was the intent.
What should I do with the customers acquired during Black Friday?
Tag them as a cohort and measure repeat purchase rate at 30, 60 and 90 days against your normal cohorts. Around half of repeat buyers return within 30 days, so you find out quickly. If the cohort does not repeat, the discount bought volume rather than customers, and that changes what the promotion was actually worth.
Planning Q4 or reviewing one that just ended and want a second set of eyes on the numbers? Reach out to one of our experts and we will walk through it with you.
