Creating an experiment
1
Open Experiments
Go to Insights → Experiments.
2
Start a new experiment
Click New Experiment.
3
Name the hypothesis
Enter a name and description. The description should capture your hypothesis, for example “Pinning new releases to top 3 will increase click-through rate by 15%.”
4
Configure variants
Add at least two variants with Add variant:
- Control - the baseline experience (typically your current configuration).
- Treatment - the change you want to test.
5
Set traffic
Set each variant’s Traffic share. The total is shown and should be 100%.
6
Create the experiment
Click Create Experiment.
Variant configuration
Each variant has:
Change one thing per variant, so a difference in results has one cause. To measure whether your rules help at all, give the treatment a recipe whose pipeline has the Rules stage turned off, with required eligibility constraints preserved. An empty Include rules selection does not necessarily disable rules.
Traffic assignment
A stable user ID receives a consistent variant while the variant order and traffic shares stay unchanged. Use the same user ID across devices when you want consistent assignment. Changing traffic shares can move users between variants and affect how historical metrics are grouped. Experiments can overlap. Avoid changing the same context through several experiments at once unless you have designed and checked that interaction.Experiment lifecycle
To change status, open the experiment and use the status buttons on the Setup tab. The History tab records every change to the experiment.
Measuring results
The Results tab shows computed metrics for each variant.Available metrics
Lift calculation
For each treatment variant, the Results tab shows lift vs. control:- Positive lift (green) means the treatment outperformed the control.
- Negative lift (red) means the treatment underperformed.
- Lift is calculated as
(treatment_metric - control_metric) / control_metric.
Refreshing metrics
Select Refresh metrics to recompute from the latest data. Metrics are computed by:1
Query served users
Query all users who were served recommendations during the experiment window.
2
Reassign variants
Deterministically re-assign each user to a variant using the same hash as the live engine.
3
Aggregate metrics
Aggregate served impressions and user events per variant.
Best practices
- Choose a suitable measurement window for your traffic, business cycle and sample-size needs.
- Don’t change rules mid-experiment unless you intentionally want to measure the impact of the change.
- Use meaningful sample sizes. If one variant has very few users, the metrics will be noisy. Ensure traffic fractions give each variant enough volume.
- Document your hypothesis in the experiment description so you can review what you were testing months later.
- Complete experiments when done. This sets the end date and freezes the measurement window.

