Data freshness

  • Updated

This topic describes how to:

  • Determine when results were last updated for your experiments and campaigns
  • View new results data as it becomes available

Data freshness describes the length of time it takes Optimizely Experimentation to collect, process, and deliver data via the Results page or API. We consider data freshness to be critical to our business, so we built a fast results pipeline that helps you make validated decisions at scale. Results are typically available within 5 to 10 minutes of Optimizely Experimentation receiving the data.

To handle several billion events per day, Optimizely Experimentation’s distributed event infrastructure queues and processes events, then holds the processed events in a low-latency data store. This infrastructure ensures that events are ready for queries when you visit the Results page. After events are attributed to sessions and users, Optimizely Experimentation applies statistical tests to the data (learn more about Stats Engine). Events are displayed as the metrics that you use to make business decisions.

Optimal data freshness offers these advantages:

  • Early validation – confirm experiment setup and mitigate risk using first results

  • Support for time-sensitive decision-making, which is important for:

    • Headline testing

    • High-traffic testing

    • Holiday sales

    • Testing during critical news cycles

  • QA without waiting: send events to confirm your experiment setup

Determine your results data freshness

Check the freshness of your current data on the Results page. The Results last updated: heading at the top of the page lists the date and time of the results you’re currently viewing.


A banner will appear at the top of the Results page when fresher results data are available. Click the link in the banner to reload the page and view the new results data.


Data freshness throttling

When an experiment or campaign experience reaches a sample size of 1 million users, Optimizely Experimentation may throttle the refresh rate to up to one hour in order to maintain the highest accuracy of results.