How Traffic Stabilization works

Traffic stabilization is designed to keep Parallel tests fair when Apple Ads distributes traffic unevenly across variants.

This article explains what Stabilize Traffic does, when it applies, and what rules the system follows. To learn how Parallel tests work overall, learn what is the Parallel method in CPP A/B Testing.

Why Traffic Stabilization is useful

In a Parallel test, multiple ads run at the same time and share identical properties.

Because traffic distribution cannot be directly controlled, Apple Ads may favor one variant and allocate most of the traffic (impressions) to it, which can bias the test outcome.

To help prevent this, CPP A/B Testing provides the Stabilize Traffic option for the one ad group, multiple custom product pages Parallel test option.

How “Stabilize Traffic” works

When Stabilize Traffic is enabled:

The system monitors each variant’s traffic hourly.
If one variant starts receiving disproportionately high traffic, it is temporarily paused.
Pausing continues until other variants catch up.

This feature ensures all variants receive more balanced exposure, so results are more accurate and reliable. However, if your priority is to keep all variants live at all times, you may want to disable this option when running a Parallel test.

The 25% traffic distribution rule

The system aims to keep the difference in traffic distribution between:

The variant receiving the most traffic, and
The variant receiving the least traffic

within 25%.

This monitoring-and-pausing approach is intended to maintain fair distribution with minimal status changes.

When traffic stabilization applies

Traffic stabilization only applies in single ad group Parallel test, where multiple variants run at the same time, and traffic distribution can become uneven.

Need more help?

If you have further questions on the process, contact your dedicated Customer Success Manager or contact the support team via live chat!

How Traffic Stabilization works