Skip to main content

​
Using Qualifying Events

Qualifying events are used to simulate exposures for power analysis, and to filter exposures to users who triggered a specific event. Setting up a Qualifying Event is identical to setting up an Assignment Source, except they do not require experimental information.
Please note that the qualifying event must occur after the exposure as indicated by their respective timestamps.
Context columns can be used to filter the qualifying event for power analysis - for example you might have a Qualifying Event for page load, and filter to different page identifiers for power analyses of experiments on different surfaces.

​
Filter by Qualifying Events

Statsig has best-in-class controls around using qualifying events to filter exposures in an experiment in cases of over-exposure.
qualifying event filter
In the image above:
  • We’re using forwarded sdk events from Statsig to filter exposures. This could also be a single-event source or any data source
  • We’ve chosen to replace the actual exposure timestamp with the first observed qualifying event - this will make our metric timelines and cohort timelines more accurate
  • We only count qualifying events from within an hour of an exposure event - this helps to avoid issues with late-landing attribution
  • We’ve added a filter to only include events from the www.statsig.com domain
Some customers prefer this flexibility, and many just set up qualifying events as individual events to plug into their analyses. You can often identify over-exposed experiments by observing uniformly low participation rate on all metrics.

​
Power Analysis

Qualifying events can be used in power analysis as a way to estimate your experimentation population by how many people historically hit your proposed trigger event.
power analysis with qualifying event
These can be filtered by event attributes, or by entity properties (e.g. users who triggered this event and are also in a segment or country).

​
Example Data

For example, you could pull from page load event logging directly and save it as a qualifying event called Page Load: