The average session duration in seconds per device during the specified period.
Avg. session dur. per device = sum of average sessions durations of each device / number of devices.
The session is a time interval during which the user has not interrupted interaction with the application. For mobile apps, the session starts with the launch and stops when the application has spent more than 30 seconds in the background. For web apps, the session starts with page view and stops when more than 30 minutes have passed since the last view.
Avg. unique session dur., sec. – Flow metric
Avg. unique session dur., sec. CA – Current Attribution metric
Avg. unique session dur., sec. LT – LifeTime metric
Avg. unique session dur., sec. AT – Attribution Time metric