Incrementality
In practice, for a UK buyer
The paragraph above is the neutral answer. This is the part a vendor glossary leaves out.
Sold by most platforms in this category and refused by almost none, which is the difference worth caring about. AdBuyMCP runs a matched-market geo-lift test and puts a power analysis in front of it at 5% significance and 80% power. If the design cannot detect a plausible lift, it returns an underpowered verdict, the required sample days and the minimum detectable effect — and no lift figure at all. Its own words: reporting a number from it would be reporting noise. Nothing here has produced a causal result for a customer, because nothing has run live.
Goes deeper: Four verbs, kept apart
What this one connects to
Most confusion in media buying comes from two adjacent terms being used interchangeably, so these are the neighbours worth reading next.
Geo-lift test
An experiment that runs advertising in some geographic markets and withholds it from comparable others, then compares outcomes between them. The causal design that needs no login, pixel or match rate.
Holdout
A group deliberately excluded from seeing a campaign and kept as a comparison against the group that was exposed to it. Without one, the counterfactual — what would have happened anyway — has to be assumed rather than observed.
Statistical power
The probability that a test will detect a real effect of a given size, if an effect of that size genuinely exists in the population being measured. A design with low power will usually miss a genuine effect, raises the share of the results it does produce that are noise rather than signal, and exaggerates the size of the effects it does detect.
Attribution
Assigning credit for an outcome to the advertising touchpoints that preceded it, according to a rule the advertiser chose. A description of correlation in a conversion path, not a demonstration that the advertising caused anything.
More on measurement and evidence
What you can prove afterwards, and the difference between a number that means something and a number that does not.
45 minutes. Bring a real brief and we compile it live. You describe one audience and watch it compile into seven targeting specifications, each with the score for how much of the definition survived.
Talk it through