Ad measurement glossary
The terms Amazon and Meta advertisers run into, defined in plain words. Each one links to a guide or calculator that goes further. For how Spillmark measures what ads cause, see how lift is calculated.
A
- ACoS (advertising cost of sales)
- Ad spend divided by the sales your Amazon ads are credited with. A 25% ACoS means $1 of ads for every $4 of credited sales. It's the inverse of ROAS. What is ACoS? →
- Amazon Attribution
- Amazon's free tool for measuring ads outside Amazon, such as Meta ads. You tag each ad's link, and Amazon reports the clicks and sales within 14 days of a click on the tag. Facebook ads for Amazon →
- Attribution model
- A rule for sharing credit for a sale among the ads a customer touched before buying, such as giving it all to the last click or splitting it across several. Attribution models →
- Attribution window (conversion window)
- How long after a click or view a purchase still counts toward an ad. Meta's standard is 7 days after a click and 1 day after a view; Amazon Sponsored Products uses 7 days after a click. Attribution windows by platform →
B
- Blended ROAS (MER, marketing efficiency ratio)
- All revenue divided by all ad spend, across every channel. It avoids double-counting between platforms but can't say which ads work. TACoS and blended ROAS calculator →
- Brand Referral Bonus
- An Amazon program that credits brands, on average, 10% of qualifying sales from tagged ads outside Amazon, applied against referral fees. Brand Referral Bonus calculator →
- Break-even ROAS (and break-even ACoS)
- The ROAS at which the margin on credited sales exactly pays for the ads: 1 divided by your margin before ads. Break-even ACoS is that margin itself. Break-even ROAS and ACoS calculator →
C
- CAC (customer acquisition cost)
- What you spend to win one new customer. Compare it with what the customer is worth over time, not just their first order. Max allowable CAC calculator →
- CAC payback period
- How many orders, or how many days, until a new customer's margin pays back what you spent to win them. CAC payback calculator →
- Confidence interval (uncertainty range)
- The range a measured effect probably falls in, given the noise in the data. A lift of 12% with a range of 4% to 20% is more useful than 12% alone. How lift is calculated →
- Contribution margin
- What a sale leaves after the costs that come with it: product cost, marketplace or payment fees, shipping and ads. It's the profit that pays for fixed costs. What is contribution margin? →
- Conversion lift study
- A randomized test run by an ad platform, such as Meta, that withholds ads from a random group and compares purchases. It only sees purchases the platform can track. Conversion lift vs. brand lift →
D
- Difference-in-differences
- Compares how sales changed in a test group with how they changed in a control group over the same period, so shared trends cancel out. Difference-in-differences →
F
- FBA fee (FBA fulfillment fee)
- Amazon's per-unit fee to pick, pack and ship an order it fulfills. It depends on the packaged size and weight, the price and the season. Amazon FBA fee calculator →
G
- Geo test (geo lift test, geo holdout)
- An experiment that turns ads off, or on, in some regions and compares sales with regions where nothing changed. Geo testing →
H
- Halo effect
- Sales an ad causes that no report credits to it, such as Amazon purchases by shoppers who saw a Meta ad and searched Amazon later. Halo effect calculator →
- Holdout group (control group)
- The people or regions that don't see your ads during a test. Their sales show what would have happened without the ads. Holdout groups →
I
- Incremental revenue
- The extra dollar sales your ads caused: revenue with the ads minus the revenue you would have had without them. The dollar form of incremental sales. What is incremental revenue? →
- Incremental sales
- The extra orders your ads caused: sales with the ads minus the sales you would have had without them, usually estimated with a holdout test. What are incremental sales? →
- Incrementality (incremental lift)
- The sales your ads cause: the ones that wouldn't have happened without them. It differs from attributed sales, which are the ones ads got credit for. What is incrementality? →
- Incrementality measurement
- Methods that estimate caused sales, usually holdout tests by user or region, sometimes models checked by those tests. For Meta ads that sell on Amazon, geo holdouts are the usual path. Incrementality measurement →
- iROAS (incremental ROAS)
- Sales the ads caused, measured with a holdout test, divided by ad spend. It can be much higher or lower than the ROAS a platform reports. Incremental ROAS calculator →
M
- Marketing incrementality
- Incrementality applied to marketing spend: the sales caused by the ad dollars you are evaluating, not the revenue platforms credit under their windows. Marketing incrementality →
- Marginal ROAS
- What the next dollar of ad spend returns, as opposed to the average across all spend. Returns usually shrink as spend grows. Marginal ROAS calculator →
- Marketing mix modeling (MMM, media mix modeling)
- A statistical model that estimates each channel's effect from spend and sales over time, without tracking individual people. MMM vs. incrementality testing →
- Matched markets
- Test and control regions chosen because their sales have moved in step in the past, so a difference during a test points to the ads. Matched market testing →
- Minimum detectable effect (MDE)
- The smallest lift a test is likely to detect, given its size and length. If your ads' likely effect is smaller, the test will probably say "no clear effect". Holdout test sample size calculator →
- Multi-touch attribution (MTA)
- Any attribution model that splits credit across several ad interactions, by a fixed rule such as linear or by a model learned from data. Attribution models →
L
- Last-click attribution
- Gives all the credit for a sale to the last ad clicked before buying. Simple, but it ignores everything earlier in the path. Attribution models →
- LTV (customer lifetime value)
- What a customer is worth over all their orders, usually counted as margin rather than revenue. It sets how much you can pay to win one. Subscribe & Save LTV calculator →
R
- Referral fee
- Amazon's commission on each sale: a percentage of the total price, set by product category, with a per-item minimum in most categories. Amazon referral fees by category →
- Reorder point
- The stock level at which you need to reorder so new stock arrives before you run out, given daily sales and lead time. Reorder point and ad pacing calculator →
- ROAS (return on ad spend)
- Revenue credited to your ads divided by ad spend. A ROAS of 4 means $4 of credited revenue per $1 spent. It measures revenue, not profit. What is ROAS? →
S
- Synthetic control
- Builds a stand-in for a test region from a weighted blend of other regions, then compares the real region with its stand-in. It's the method behind GeoLift. Synthetic control →
T
- TACoS (total advertising cost of sales)
- Ad spend divided by all your sales, including organic ones. It shows how much of the business depends on ads. TACoS calculator →
V
- View-through attribution
- Credit given to an ad someone saw but didn't click, if they buy within a short window. Meta's standard setting counts purchases within 1 day of a view. Attribution models →
Measure it on your own brand
Spillmark runs geo holdout tests for Meta ads and measures what they cause on Amazon, with the math shown. Read the guides or try the free calculators.
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