Historical metrics are used for tracking KPIs, diagnosing issues, and measuring viewers' quality of experience. Metrics are calculated using the video views that have been completed and are bucketed on the view end time for quality of experience metrics and view start time for engagement metrics. Historical metrics provide a large collection of dimensions that can be used to aggregate quality of experience based on view metadata. You can also easily compare experiences across viewer populations to, for example, find issues with specific devices or geographies.

Historical metrics are similar but not directly comparable to the real-time metrics in the Real-time APIs. These metrics are aggregated for long-term storage historical reporting and are generated using different viewer populations.