A lookalike population can change in response to dynamic fluctuations in the first-party data. As a result, the segment populations can change when the lookalike model is retrained. Some customers are sensitive to first-party data fluctuations and need a way to limit unexpected variation in their populations.
Use the Lookalike Reach Protection Tool to set maximum and minimum limits (reach protection) and enforce segment population thresholds after lookalike models are retrained. The limits are based on shrink and growth percentages. The default values are 0.9 shrink to 1.1 growth, or you can set your own limits as a percentage range. The limits you set take effect within 24 hours.
The reach protection limits apply to all instance segments after they are set. The Audience Studio Manage Segments page displays an eye icon next to the segment names that are being monitored. A lock icon indicates that the segment is protected against dropping under or rising above the limits whenever a lookalike model is retrained.
After you turn Reach Protection ON, the segment is monitored for fluctuations in reach size. The eye icon is displayed when Audience Studio is monitoring the reach of all the lookalike segments.
Audience Studio recomputes the lookalike segments week over week, as it checks the new reach (population size) against the limits that you set when you turned reach protection on. If the reach size grows or shrinks outside the intervals chosen, the segments are now frozen and locked, and the eye icon will be replaced with the lock icon. This happens because the previous reach has been protected (as the new reach has a spike that puts it outside the desired range for that similarity score).
If your segment populations aren’t sensitive to first-party data fluctuation, it’s not necessary to set reach protection thresholds. However, when setting reach protection thresholds, the data can become stale when the segment population remains frozen for too long.
To set limits, on the Manage Segments tab, click Enable Reach Protection. Set your limits and click Apply.
If you have questions about using the Lookalike Reach Protection tool in your environment, contact the Salesforce Audience Studio Support team for assistance.