Atlas now provides the ability to review descriptive statistics about an OMOP CDM. This functionalit was originally built by as part of the Achilles working group.
You must install Achilles in order to use this feature in Atlas. See the installation and setup guide for more details.
In the top right of the data sources page you will find two drop downs: Data Sources and Reports. The data sources pull down will contain the list of data sources that were configured when setting up installation and setup guide. The reports section will contain the list of available reports.