Dimension Analysis
A powerful way to understand who or what is causing a metric movement, dimension analysis lets you break down an experiment result by unit or action.
To view the Pulse result breakdowns for all categories within a metric, select the (+) sign next to the metric.
Unit dimensions
Unit dimensions refer to unit-level attributes that are either part of the user object you log to Statsig, provide as part of your assignment data, or provide through an Entity Property. Examples of these attributes are operating system, country, region, or user segments.Using explore queries, you can filter to specific unit dimensions or group results by a dimension. For example, you can view results for users in the US, or view results for users on iOS grouped by their country.Statsig chooses the dimension based on the last available record at or before exposure. Statsig doesn't use information from after the unit is exposed to a given experiment in the experiment analysis, because using post-exposure data can lead to data leakage and imbalanced comparisons.
Metric dimensions
Metric dimensions break down a metric's results based on the values in columns from your metric source for a given metric. You configure these breakdowns per-metric, after which Statsig calculates them for that metric across all pulse results.Unlike Unit Dimensions, Metric Dimensions are not mutually exclusive. For example, with a unit dimension a user can only be from one country for the purpose of pulse analysis, but a user on an e-commerce website could buy "clothes", "books", and "snacks" within a "total purchases" metric and contribute to each of those dimensions as well as the overall value.
Default behavior
By default, dimensional analysis:
- only considers dimensions with at least 100 units in the experiment that participated (had a non-zero value)
- chooses the top 10 dimensions by total value, and puts all others into an "OTHER" bucket.
These defaults prevent extreme results, avoid cases where centrality assumptions fail due to low sample sizes on a specific dimension, and limit excessive multiple comparisons on the tail end of dimensional breakdowns. This behavior is configurable. Contact Statsig support to evaluate whether your use case warrants a change.
Precomputed dimension loading timing
For precomputed user dimensions that are configured and run on a schedule, Statsig processes dimension data asynchronously and it may take a few minutes to become available after the main experiment results load. You may temporarily see "No dimensions available for this time range" messages while Statsig processes the data, especially after the first reload of the day. This is expected behavior. Wait a few minutes and refresh the page to see the dimensional breakdowns.
This timing behavior only affects precomputed user dimensions. User-triggered dimensional analysis doesn't experience this delay.
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