Google Optimize Data in Google Analytics – Why are the numbers different?

Google Optimize Data in Google Analytics

When you create an experiment in Google Optimize, you can choose to send the data to Google Analytics by connecting your Google Optimize account with Google Analytics. When you do that all your experiment data starts to show up up in Google Analytics, see the image below:

Why Do Google Optimize and Google Analytics Show Different Numbers?

There are two reasons why the numbers differ

1. The data is first processed in Google Analytics and then gets pushed to Google Optimize. It can take up 12 hours before the data is pushed and updated in Optimize and hence at any given time the two numbers won't match.
2. The conversion rate numbers in Google Analytics are the actual conversion rates while the numbers in Google Optimize are modeled (estimated) based on the performance of the different variants.

Which number to use to access the outcome of the experiment?

Google recommends using the Optimize numbers since those a modeled based (expected) based on the performance of the variants.  More information is available at https://support.google.com/optimize/answer/6323229?hl=en