On the Health menu, you will find Sources data quality.
You can visualize the evolution of your event data quality over time, filter by sources or environment (default to Production)
You can setup an alert to know in realtime if some of your event violate your validation rules.
You can analyze in detail each event and have more details about errors, and a shortcut to fix the error in the Data Cleansing feature.
FAILED the event is in error status, can be caused by an error 404, a timeout, etc...
FILTERED the event has been filtered (based on the conditions created in Normalized Datalayer.)
INVALID ACCEPTED means the property has been removed, but it is not blocking for the event, this one has been received without the concerned property. You should fix the property to receive it.
INVALID REJECTED means one or many properties are missing or don't have good values. As a result, the full event was rejected, you should fix it to receive the event.
VALID the event has been collected correctly, this means your sources are sending the data expected in your specifications.
You can also visualize the data quality for a specific source, when you click on a source, you have a dedicated tab 'Data Quality'tap available with same info but filtered for the source you selected:
The quality score of events is represented by a weather icon:
sunny if the percent of correct events is equal to 100%
cloudy between 95% and 99.99%
rainy between 90 and 95%
stormy below 90%