Check the generated rules, then the people they select. Write down who should qualify and who must be excluded. Compare that brief with the saved conditions, including subscription status, event windows and AND/OR grouping. Inspect profiles that should pass and profiles that should fail. Approve the audience only when those checks agree; a plausible segment name or count is insufficient.
An AI-created segment has several things to review: what you asked for, the conditions the tool generated, and the contacts those conditions select. This guide covers rule-based audiences generated from natural language, where you can inspect the definition. It does not validate an opaque customer cluster or a churn model.
The question here is whether the audience implements your campaign’s rules. For the choice between segmentation methods, see how AI customer segmentation differs from RFM.
What should the segment do before you ask AI to build it?
Write an audience brief that makes inclusion and exclusion testable: the campaign purpose, channel eligibility, qualifying activity, time windows and people to leave out. Decide how missing data should be treated. Then compare the generated definition with that brief rather than asking whether its name sounds right.
For example, use this invented campaign brief, not a recommended reactivation schedule:
| Decision | Intended rule |
|---|---|
| Purpose | A return-to-store campaign for past customers |
| Email eligibility | Subscribed to email marketing and able to receive it |
| Purchase history | At least one recorded order in the last 180 days |
| Recent-purchase exclusion | Zero recorded orders in the last 30 days |
| Missing purchase history | Do not qualify without the required recorded order |
Those windows belong to this illustration. Choose your own from the campaign’s purpose; do not let the generator silently turn “past customers” into an arbitrary period.
For a subscriber-only campaign, keep eligibility as an explicit requirement. Klaviyo’s subscriber guidance distinguishes being in a list from having email consent and advises restricting marketing segments to profiles who are subscribed and can receive email marketing. A purchase or an email address should not substitute for the subscription rule you intended.
This is a subscription-based audience policy, not a complete legal assessment. Our guide to emailing people who never opted in addresses that separate sending-permission question.
Which generated conditions need checking?
Compare every generated condition with the brief: the event or property, comparison operator, value, timeframe, exclusions and AND/OR grouping. Check for omitted conditions as well as incorrect ones. In Klaviyo’s Define with AI documentation, the user remains responsible for the definition; the review instructions explicitly include metrics, timeframes, connectors and missing conditions after partial generation.
Define with AI requires a paid account and is unavailable for EU-hosted accounts.
Start with what the rule actually reads. Is the purchase condition using the order event you intended? Is its window the campaign’s window? If a product filter is involved, inspect an actual event to verify the field and value. The segment-building documentation says event filters use top-level properties, not nested ones, and their text values are case-sensitive. A description that sounds like the correct product is not a substitute for checking the recorded value.
Next, read the grouping aloud. AND requires every connected requirement; OR allows a qualifying alternative. For the invented brief, the intended logic is:
Eligible AND ordered within 180 days AND no orders within 30 days
Changing the first pair to (Eligible OR ordered within 180 days) lets a past buyer pass that group without being eligible. Read the saved definition’s grouping, not just the prompt’s sentence. The AND/OR reference explains that this builder groups OR-connected conditions and requires each group joined by AND.
Exclusions need the same care. When you mean “exclude people matching either disqualifier,” separate negative requirements need to hold together. Joining “does not match exclusion A” and “does not match exclusion B” with OR can admit someone who matches A but not B. Check a profile from each excluded group.
Finally, test missing values explicitly. In this platform’s null-value documentation, a negative profile-property condition does not automatically include contacts whose property is unset. If your intended audience includes them, the definition needs an explicit “is not set” alternative. That alternative belongs inside the appropriate group; it should not provide a route around email eligibility. Other tools may handle missing values differently, so check their behavior before copying the rule.
Which profiles should you test against the audience?
Check contacts you expect to qualify and contacts you expect to fail, using their actual subscription state, properties and recorded events. Include cases that distinguish the intended rule from a plausible wrong one. Investigate any mismatch before using the segment. These checks can expose a defect; a handful of passing examples cannot prove every member is correct.
For the invented brief above, the following fictional profiles have these expected results at the same evaluation time. Eligible means both subscribed and able to receive email marketing; each stated last order is the most recent recorded order.
| Profile | Facts | Expected result and reason |
|---|---|---|
| Ada | Eligible; last order 60 days ago | Include: purchase within 180 days, none within 30 |
| Ben | Eligible; last order 10 days ago | Exclude: fails the recent-purchase exclusion |
| Cy | Unsubscribed; last order 60 days ago | Exclude: fails eligibility |
| Dee | Eligible; no recorded orders | Exclude: fails the prior-purchase requirement |
| Eli | Eligible; only order 220 days ago | Exclude: purchase is outside the 180-day window |
The wrong OR group, (Eligible OR prior purchase) AND no recent purchase, would include Cy, Dee and Eli. Cy passes because prior purchase bypasses eligibility; Dee and Eli pass because eligibility bypasses the purchase requirement. Only Ben still fails, because the recent-purchase exclusion sits outside the OR group. Under the intended all-AND rule, all four are excluded.
Use comparable cases in your account, plus contacts near a time-window boundary and with relevant missing fields. For a mismatch, record the expected result and the condition or source event that explains the actual result. Correct the definition or resolve the data question, then repeat the affected checks.
How do you inspect counts and sample members?
Use the segment preview to inspect membership, then open included profiles and compare their facts with your brief. Treat the displayed size as an estimate. In Klaviyo’s preview, incomplete or invalid criteria can be omitted from the count, so resolve those errors before relying on it; the feature supports segments with 100 or fewer criteria.
In the same platform, go to Audience → Lists & segments, open the segment, and choose Edit definition. Select Preview details to see estimated size and sample included profiles; open a listed profile to investigate why it qualifies. The preview guide notes that final membership may differ slightly from the estimate. Check your ESP’s workflow before following these menu instructions elsewhere.
Use the preview’s members for inclusion checks. Separately inspect known excluded profiles against the definition; an included-members preview cannot by itself show whether the people you intended to leave out were handled correctly. Do not accept a count merely because it is close to last month’s campaign: the test is whether the intended rules hold.
What should you save before approving the segment?
Save the audience brief, segment ID and final definition, review time, observed membership count, checked profiles with expected and actual results, unresolved issues and approver. Recheck the audience and campaign recipient settings before use. A dynamic segment can gain or lose members after review, so approval needs to identify the definition and evaluation time.
This is a practical application of NIST’s 2023 AI Risk Management Framework, which calls for contextual testing, documented evaluation and human oversight. NIST does not prescribe this email checklist.
Keep a short decision record:
| Save | What it lets the next reviewer check |
|---|---|
| Brief and final definition | Whether the implemented audience still matches the intended campaign |
| Review time, count and profile checks | What was observed and which cases were actually checked |
| Issues, fixes and approver | Whether an unexpected inclusion or exclusion was resolved before use |
If a required condition is missing or an excluded profile qualifies, hold the audience for correction. Passing this check answers whether the generated segment matches the reviewed rules. Whether the campaign earns profitable repeat purchases remains a separate question.
Sources
- How to market to profiles you shouldn't email · 20 Oct 2026
- How to define segments with AI · 20 Jan 2026
- Getting started with segments · 20 Jan 2026
- AND vs. OR reference · 20 Feb 2026
- Understanding how segment conditions evaluate null or empty values · 27 Mar 2026
- How to preview segments · 7 Jul 2025
- NIST AI RMF 1.0, Core