Experiment library
Reduce customer acquisition cost · method v1
Search-term exclusion test
Exclude search terms that spend without producing collected payments in a subset of campaigns, and check whether paid customer volume holds.
- Hypothesis
- A set of search terms consumes budget without producing paying customers; excluding them lowers acquisition cost without losing paid volume.
- Change
- Add negative keywords for the selected terms in treated campaigns or regions.
- Who is included
- Paid search campaigns with enough monthly conversions to compare.
- Compared with
- Matched campaigns or regions where the terms stay active.
- Assignment
- Split by geography or campaign pairs, fixed before the test starts.
- Measurement
- Cost per collected paid customer and paid customer count per arm. Unmatched payments are reported separately, never allocated.
Worked example
$12,000 a month with 18% on the candidate terms puts $2,160 at stake. If paid customers in treated regions fall by less than the spend saved, cost per paid customer improves. The test is useful only when payments can be matched to campaigns by an explicit campaign value.
Evidence you need
- Search terms report with cost
- Campaign or region on each payment
- Paid customer count per region per week
Implementation steps
- Pick terms using spend and the absence of matched payments
- Fix treated and comparison regions
- Apply exclusions to treated regions only
- Run for at least four weeks
- Compare cost per paid customer and paid volume
Cost components
- Media spend during the test
- Setup time in the ad account
- Reconciliation of payments to campaigns
Stop if
- Paid customers in treated regions fall more than 20% below comparison for two consecutive weeks
Scale if
- Lower cost per paid customer with paid volume within 10% of comparison
Does not apply when
- Accounts with too few conversions to split
- When payments carry no campaign value at all
Adapt this experiment to your business
Your values stay in this browser until you sign in, then become a private protocol that records this method and version.