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Holdout Test in Advertising: Definition | Particular Audience

A holdout test withholds a campaign from a random group of shoppers to measure the campaign's true effect.

Holdout test

A holdout test is an experiment where a random share of eligible shoppers is deliberately not shown a campaign. Comparing their behaviour with shoppers who could see it reveals the campaign's true effect. Holdouts are the standard way to measure incrementality in retail media, and they work for creative, placements and whole programmes, not just individual ads.

Good practice

Randomise properly, fix the group for the test period and agree the success measure before starting.

How Particular Audience does it

Related guides

  • Incrementality: Incrementality is the extra sales caused by advertising, measured against a group that did not see it.
  • How to measure retail media incrementality: Use holdout groups to separate sales caused by retail media from sales that would have happened anyway, and report brand halo.

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